As filed with the Securities and Exchange Commission on July 26, 2000.

                                                       Registration No. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549
                                    --------

                                    FORM S-8

                             REGISTRATION STATEMENT

                                      UNDER

                           THE SECURITIES ACT OF 1933
                                 --------------

                               UNITIL CORPORATION
             (Exact name of registrant as specified in its charter)

         New Hampshire                                         02-0381573
(State or other jurisdiction of                              (I.R.S. Employer
incorporation or organization)                              Identification No.)

             6 Liberty Lane West, Hampton, New Hampshire 03842-1720
           (Address of principal executive office, including zip code)

                               ------------------



                               UNITIL CORPORATION
                    TAX DEFERRED SAVINGS AND INVESTMENT PLAN

                            (Full title of the plan)




                             Anthony J. Baratta, Jr.
                            Senior Vice President and
                             Chief Financial Officer

                               UNITIL CORPORATION
                               6 Liberty Lane West
                        Hampton, New Hampshire 03842-1720
                                 (603) 772-0775
(Name, address, and telephone number, including area code, of agent for service)



                                   Copies to:
                             David S. Balabon, Esq.
                     LEBOEUF, LAMB, GREENE & MACRAE, L.L.P.
                               260 Franklin Street
                           Boston, Massachusetts 02110
                                 (617) 439-9500


                               ------------------

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<S>                             <C>             <C>                     <C>                   <C>
           Title of                                Proposed maximum       Proposed maximum
           securities            Amount to be       offering price       aggregate offering
      to be registered 1         registered 2         per share3               price3         Amount of registration fee4

         Common Stock,              150,000            $26.6875              $4,003,125               $1,056.83
         no par value               shares
=========================================================================================================================
</TABLE>

================================================================================
1 In addition,  pursuant to Rule 416(c) under the Securities  Act of 1933,  this
Registration  Statement also covers an  indeterminate  amount of interests to be
offered or sold pursuant to the employee benefit plan described herein.

2 In addition,  pursuant to Rule 416(a) under the Securities  Act of 1933,  this
Registration  Statement also covers any  additional  securities to be offered or
issued in connection with a stock split, stock dividend or similar transaction.

3 Estimated  solely for the purpose of calculating the registration fee pursuant
to Rule 457(h) under the  Securities  Act of 1933 on the basis of the average of
the high and low prices of the Common  Stock as reported by the  American  Stock
Exchange  on July 21, 2000 which date is within  five (5)  business  days of the
filing hereof.

4 In accordance with Rule 457(h)(2) no separate fee calculation is made for plan
interests.

================================================================================

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


Item 3.  Incorporation of Documents by Reference.
------   ---------------------------------------

     The  following  documents,  which  have  heretofore  been  filed by  Unitil
Corporation (the "Company")  and/or the Unitil  Corporation Tax Deferred Savings
and Investment  Plan (the "Plan") with the  Securities  and Exchange  Commission
(the "Commission")  pursuant to the Securities  Exchange Act of 1934, as amended
(the "Exchange Act"), are hereby  incorporated by reference in this Registration
Statement:

     (a) The  Company's  Annual  Report on Form 10-K for the  fiscal  year ended
December 31, 1999, as amended by Form 10-K/A filed with the  Commission on April
14, 2000.

     (b) The Company's Quarterly Report on Form 10-Q for the quarter ended March
31, 2000.

     (c)  The  description  of  the  Company's  Common  Stock  contained  in the
Company's  Registration  Statement  on Form 8-A  filed  with the  Commission  on
February 8, 1985,  pursuant to Section 12 of the Exchange Act, and any amendment
or  report  filed  with  the   Commission  for  the  purpose  of  updating  such
description.

     (d) The Plan's Annual  Report on Form 11-K for the year ended  December 31,
1999.

     All  documents  subsequently  filed by the  Company  and the Plan  with the
Commission  pursuant to Section 13(a),  13(c),  14 or 15(d) of the Exchange Act,
prior to the  filing of a post-  effective  amendment  that  indicates  that all
securities offered hereby have been sold or that deregisters all securities then
remaining  unsold,  shall be  deemed to be  incorporated  by  reference  in this
Registration  Statement  and to be a part hereof from the date of filing of such
documents.  Any statement  contained in a document  incorporated or deemed to be
incorporated  by reference  herein shall be deemed to be modified or  superseded
for  purposes  of this  Registration  Statement  to the extent  that a statement
contained herein or in any other subsequently filed document that also is deemed
to be  incorporated  by reference  herein modifies or supersedes such statement.
Any such statement so modified or superseded  shall not be deemed,  except as to
modified or superseded, to constitute a part of this Registration Statement.

Item 4.  Description of Securities.
------   -------------------------

         Not applicable.

                                      II-1


<PAGE>




Item 5.  Interests of Named Experts and Counsel.
------   --------------------------------------

     Paul K.  Connolly,  Jr., a member of the firm of  LeBoeuf,  Lamb,  Greene &
MacRae,  L.L.P., which is rendering an opinion on the validity of the securities
being registered  hereunder,  owns 2,631 shares of the Company's Common Stock as
of the date of this Registration Statement. Mr. Connolly is a participant in the
Company's Dividend  Reinvestment and Stock Purchase Plan and, as such,  acquires
additional shares of Common Stock at regular intervals.

Item 6.  Indemnification of Directors and Officers.
------   -----------------------------------------

     The Company is organized under the laws of the State of New Hampshire.  The
New Hampshire  Business  Corporation Act (the "Act") provides that a corporation
may indemnify an individual made a party to a proceeding  because he is or was a
director  against  liability  incurred in the  proceeding  if: (1) he  conducted
himself in good faith; and (2) he reasonably believed (i) in the case of conduct
in his official capacity with the corporation,  that his conduct was in its best
interests;  and (ii) in all  other  cases,  that his  conduct  was at least  not
opposed to its best interests;  and (3) in the case of any criminal  proceeding,
he had no reasonable  cause to believe his conduct was  unlawful.  A corporation
may not  indemnify a director (x) in  connection  with a proceeding by or in the
right of the  corporation  in which  the  director  was  adjudged  liable to the
corporation;  or (y) in connection with any other proceeding  charging  improper
personal  benefit  to him,  whether  or not  involving  action  in his  official
capacity, in which he was adjudged liable on the basis that personal benefit was
improperly  received by him. Unless limited by its articles of incorporation,  a
corporation shall indemnify a director or officer who was wholly successful,  on
the merits or  otherwise,  in the  defense of any  proceeding  to which he was a
party  because he is or was a director  or  officer of the  corporation  against
reasonable  expenses  incurred  by him in  connection  with  the  proceeding.  A
corporation  may purchase and maintain  insurance on behalf of an individual who
is or was a director,  officer,  employee, or agent of the corporation,  or who,
while a  director,  officer,  employee  or agent of the  corporation,  is or was
serving at the  request of the  corporation  as a  director,  officer,  partner,
trustee,  employee,  or  agent  of  another  foreign  or  domestic  corporation,
partnership,  joint venture,  trust, employee benefit plan, or other enterprise,
against  liability  asserted  against or  incurred  by him in that  capacity  or
arising from his status as a director,  officer,  employee, or agent, whether or
not the corporation would have power to indemnify him against the same liability
under the Act.

     Article  X of  the  Company's  By-Laws  provides  that  the  Company  shall
indemnify  any person who was or is a party or is threatened to be made a party,
to any  threatened,  pending or completed  action,  suit or proceeding,  whether
civil,  criminal,  administrative  or  investigative,  by reason of the person's
having served as, or by reason of the person's  alleged acts or omissions  while
serving as a  director,  officer,  employee  or agent of the  Company,  or while
serving at the request of the Company as a director,  officer, employee or agent
of another corporation,  partnership,  joint venture, trust or other enterprise,
against expenses,  including attorney's fees, judgments,  fines and amounts paid
in settlement or otherwise actually and reasonably incurred by him in connection
with the action, suit or proceeding,  if the person acted in good faith and in a
manner he reasonably  believed to be in or not opposed to the best  interests of
the Company,  and,  with respect to any criminal  action or  proceeding,  had no
reasonable cause to believe his conduct

                                      II-2


<PAGE>



was unlawful,  said  indemnification  to be to the full extent  permitted by law
under  the  circumstances,  including,  without  limitation,  by all  applicable
provisions of the Act. Any  indemnification  under this Article shall be made by
the Company with respect to Directors  or other  persons  after a  determination
that the person to be indemnified  has met the standards of conduct set forth in
the Act, such  determination  to be made by the Board of Directors,  by majority
vote of a quorum,  or by other persons  authorized to make such a  determination
under the Act.

     The right of indemnification  arising under this Article is adopted for the
purpose  of  inducing  persons  to serve and to  continue  to serve the  Company
without  concern that their service may expose them to personal  financial harm.
It shall be broadly construed, applied and implemented in light of this purpose.
It shall  not be  exclusive  of any  other  right to which  any such  person  is
entitled  under  any  agreement,  vote  of  the  stockholders  or the  Board  of
Directors,  statute,  or as a  matter  of law,  or  otherwise,  nor  shall it be
construed to limit or confine in any respect the power of the Board of Directors
to grant indemnity  pursuant to any applicable  statutes or laws of the State of
New  Hampshire.  The  provisions  of this  Article  are  separable,  and, if any
provision or portion hereof shall for any reason be held  inapplicable,  illegal
or  ineffective,  this  shall  not  affect  any other  right of  indemnification
existing  under this Article or  otherwise.  As used herein,  the term  "person"
includes heirs,  executors,  administrators or other legal  representatives.  As
used herein,  the terms  "Director"  and "officer"  include  persons  elected or
appointed as officers by the Board of Directors, persons elected as Directors by
the stockholders or by the Board of Directors,  and persons who serve by vote or
at the  request of the  Company as  directors,  officers  or trustees of another
organization  in which the  Company  has any direct or  indirect  interest  as a
shareholder, creditor or otherwise.

     The Company may purchase and maintain insurance on behalf of any person who
was  or is a  Director,  officer  or  employee  of  the  Company  or  any of its
subsidiaries,  or who was or is  serving  at the  request  of the  Company  as a
fiduciary of any employee benefit plan of the Company or any subsidiary, against
any  liability  asserted  against,  and  incurred  by,  such  person in any such
capacity,  or arising out of such  person's  status as such,  whether or not the
Company  would have the power to indemnify  such person  against such  liability
under the  provisions of the Act. The obligation to indemnify and reimburse such
person under this Article, if applicable,  shall be reduced by the amount of any
such  insurance  proceeds  paid  to  such  person,  or  the  representatives  or
successors of such person.

     The  Company  holds  a  directors  and  officers  liability  and  corporate
indemnification policy to protect itself and its directors,  officers, employees
and agents against any expense,  liability or loss, subject to certain limits in
coverage  and  deductibles,  whether or not the Company  would have the power to
indemnify such person against such expense, liability or loss under the Act.

Item 7.  Exemption from Registration Claimed.
------   -----------------------------------

     Not applicable.




                                      II-3


<PAGE>



Item 8.  Exhibits.
------   --------

         Exhibit No.

         4.1        Unitil Corporation Tax Deferred Savings and Investment Plan,
                    as amended and restated and effective as of January 1, 1989.

         4.2        Amendment No. 1 to Unitil  Corporation Tax Deferred  Savings
                    and Investment Plan effective as of July 1, 1996.

         4.3        Amendment No. 2 to Unitil  Corporation Tax Deferred  Savings
                    and Investment Plan effective as of January 1, 1997.

         4.4        Unitil  Corporation Tax Deferred Savings and Investment Plan
                    Trust Agreement.

         4.5        Articles of Incorporation of the Company,  as amended (filed
                    as Exhibit 3.1 to the  Company's  Registration  Statement on
                    Form  S-14,  No.  2-93769,   and   incorporated   herein  by
                    reference).

         4.6        Articles of Amendment to the  Articles of  Incorporation  of
                    the Company  (filed as Exhibit 3.2 to the  Company's  Annual
                    Report on Form 10-K for the fiscal year ended  December  31,
                    1992, and incorporated herein by reference).

         4.7        By-Laws  of  the  Company  (filed  as  Exhibit  4.4  to  the
                    Company's Registration Statement on Form S-8, 333-73327, and
                    incorporated herein by reference).

         5          Opinion of LeBoeuf, Lamb, Greene & MacRae, L.L.P.

         23.1       Consent of LeBoeuf,  Lamb, Greene & MacRae, L.L.P. (included
                    in Exhibit 5).

         23.2       Consent of Grant Thornton LLP.

         24         Power of  Attorney  (included  in Part II under the  caption
                    "Signatures").

     Pursuant  to Item  8(b) of Form  S-8,  the  undersigned  Registrant  hereby
undertakes  that it will  submit or has  submitted  the Plan and any  amendments
thereto to the Internal  Revenue Service ("IRS") in a timely manner and has made
or will make all changes  required by the IRS in order to qualify the Plan under
Section 401 of the Internal Revenue Code of 1986, as amended.

                                      II-4


<PAGE>



Item 9.  Undertakings.
------   ------------

     (a) The undersigned Registrant hereby undertakes:

        (1) To file, during any period in which  offers or sales are being made,
a post-effective amendment to this Registration Statement:

                    (i) To include any prospectus  required by Section  10(a)(3)
               of the Securities Act of 1933;

                    (ii) To  reflect  in the  prospectus  any  facts  or  events
               arising after the effective  date of the  Registration  Statement
               (or the most  recent  post-effective  amendment  thereof)  which,
               individually or in the aggregate,  represent a fundamental change
               in the  information  set  forth  in the  Registration  Statement.
               Notwithstanding the foregoing, any increase or decrease in volume
               of  securities  offered (if the total dollar value of  securities
               offered  would not  exceed  that  which was  registered)  and any
               deviation  from  the low or  high  end of the  estimated  maximum
               offering  range may be reflected in the form of prospectus  filed
               with the Commission pursuant to Rule 424(b) if, in the aggregate,
               the changes in volume and price represent no more than 20 percent
               change in the maximum  aggregate  offering price set forth in the
               "Calculation  of   Registration   Fee"  table  in  the  effective
               Registration Statement.

                    (iii) To include any  material  information  with respect to
               the  plan  of  distribution  not  previously   disclosed  in  the
               Registration Statement or any material change to such information
               in the Registration Statement;

provided,  however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the
Registration Statement is on Form S-3, Form S-8 or Form F-3, and the information
required to be included in a  post-effective  amendment by those  paragraphs  is
contained in periodic  reports filed with or furnished to the  Commission by the
Registrant  pursuant to Section 13 or 15(d) of the  Securities  Exchange  Act of
1934 and that are incorporated by reference in the Registration Statement.

        (2) That,  for  the  purpose  of  determining  any  liability  under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new Registration Statement relating to the securities offered therein, and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

        (3) To  remove from registration by means of a post-effective  amendment
any of the securities  being registered that remain unsold at the termination of
the offering.

     (b) The  undersigned  Registrant  hereby  undertakes  that, for purposes of
determining  any liability  under the Securities Act of 1933, each filing of the
Registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Securities  Exchange  Act of 1934  (and,  where  applicable,  each  filing of an
employee  benefit  plan's  annual  report  pursuant  to  Section  15(d)  of  the
Securities  Exchange  Act of 1934)  that is  incorporated  by  reference  in the
Registration

                                      II-5


<PAGE>



Statement  shall be deemed to be a new  Registration  Statement  relating to the
securities  offered  therein,  and the offering of such  securities at that time
shall be deemed to be the initial bona fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors,  officers and controlling  persons of
the  Registrant  pursuant  to  the  foregoing  provisions,   or  otherwise,  the
Registrant  has been advised that in the opinion of the  Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore,  unenforceable. In the event that a claim for indemnification
against such  liabilities  (other than the payment by the Registrant of expenses
incurred or paid by a director,  officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director,  officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been  settled by  controlling  precedent,  submit to a court of  appropriate
jurisdiction the question whether such  indemnification  by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.

                                      II-6


<PAGE>



                                   SIGNATURES

     The Registrant. Pursuant to the requirements of the Securities Act of 1933,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the  requirements  for  filing  on  Form  S-8 and has  duly  caused  this
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly  authorized,  in the Town of Hampton,  the State of New Hampshire,  on this
26th day of July, 2000.

                                             UNITIL CORPORATION


                                             By: /s/ Anthony J. Baratta, Jr.
                                                ----------------------------
                                                 Anthony J. Baratta, Jr.
                                                 Senior Vice President and
                                                 Chief Financial Officer





                                      II-7


<PAGE>





     KNOW ALL  PERSONS  BY THESE  PRESENTS,  that each  person  whose  signature
appears  below  constitutes  and appoints  Anthony J.  Baratta,  Jr. and Mark H.
Collin,   and  each  of  them   individually,   his  or  her  true  and   lawful
attorney-in-fact  and agent with full power of substitution  and  resubstitution
for  him  or her  and in his or her  name,  place  and  stead,  in any  and  all
capacities, to sign any and all amendments (including post-effective amendments)
of and supplements to this Registration Statement and to file the same, with all
exhibits  thereto,  and  other  documents  in  connection  therewith,  with  the
Securities and Exchange Commission, granting unto each such attorney-in-fact and
agent, or his  substitutes,  full power and authority to do and perform each and
every  act and  thing  requisite  and  necessary  to be done  in and  about  the
premises,  to all intents and  purposes and as fully as he or she might or could
do  in   person,   hereby   ratifying   and   confirming   all  that  each  such
attorney-in-fact  and agent, or his substitutes,  may lawfully do or cause to be
done by virtue hereof.

     Pursuant  to  the   requirements  of  the  Securities  Act  of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the date indicated:



Signature                             Title                            Date

/s/ Michael J. Dalton                 Director, President and      July 26, 2000
---------------------                 Chief Operating Officer
Michael J. Dalton


/s/ Robert G. Schoenberger            Director, Chairman of        July 26, 2000
--------------------------            the Board and Chief
Robert G. Schoenberger                Executive Officer


/s/ William E. Aubuchon, III          Director                     July 26, 2000
----------------------------
William E. Aubuchon, III


/s/ Albert H. Elfner, III             Director                     July 26, 2000
-------------------------
Albert H. Elfner, III


/s/ Ross B. George                    Director                     July 26, 2000
------------------
Ross B. George



                                      II-8

<PAGE>




Signature                             Title                            Date

/s/ Bruce W. Keough                   Director                     July 26, 2000
-------------------
Bruce W. Keough

/s/ Eben S. Moulton                   Director                     July 26, 2000
-------------------
Eben S. Moulton

/s/ M. Brian O'Shaughnessy            Director                     June 26, 2000
--------------------------
M. Brian O'Shaughnessy

/s/ J. Parker Rice, Jr.               Director                     July 26, 2000
-----------------------
J. Parker Rice, Jr.


/s/ Charles H. Tenney III             Director                     July 26, 2000
-------------------------
Charles H. Tenney III


/s/ Joan D. Wheeler                   Director                     July 26, 2000
-------------------
Joan D. Wheeler


                                      II-9

<PAGE>



     The Plan.  Pursuant to the  requirements of the Securities Act of 1933, the
trustees (or other persons who administer  the employee  benefit plan) have duly
caused  this  Registration   Statement  to  be  signed  on  its  behalf  by  the
undersigned, thereunto duly authorized, in the Town of Hampton, the State of New
Hampshire, on this 26th day of July, 2000.

                                               By:  Plan Administrator

                                               By:/s/ Mark H. Collin
                                                  ------------------
                                                     Mark H. Collin
                                                     Treasurer and Secretary







                                      II-10

<PAGE>



                                  EXHIBIT INDEX

Exhibit
  No.          Title of  Exhibit

4.1            Unitil  Corporation Tax Deferred  Savings and Investment Plan, as
               amended and restated and effective as of January 1, 1989.

4.2            Amendment No. 1 to Unitil  Corporation  Tax Deferred  Savings and
               Investment Plan effective as of July 1, 1996.

4.3            Amendment No. 2 to Unitil  Corporation  Tax Deferred  Savings and
               Investment Plan effective as of January 1, 1997.

4.4            Unitil Corporation Tax Deferred Savings and Investment Plan Trust
               Agreement.

4.5            Articles of  Incorporation  of the Company,  as amended (filed as
               Exhibit 3.1 to the Company's Registration Statement on Form S-14,
               No. 2-93769, and incorporated herein by reference).

4.6            Articles of  Amendment to the  Articles of  Incorporation  of the
               Company  (filed as Exhibit 3.2 to the Company's  Annual Report on
               Form 10-K for the  fiscal  year  ended  December  31,  1992,  and
               incorporated herein by reference).

4.7            By-Laws of the  Company  (filed as Exhibit  4.4 to the  Company's
               Registration   Statement   on  Form  S-8,  No.   333-73327,   and
               incorporated herein by reference).

5              Opinion of LeBoeuf, Lamb, Greene & MacRae, L.L.P.

23.1           Consent of LeBoeuf,  Lamb, Greene & MacRae,  L.L.P.  (included in
               Exhibit 5).

23.2           Consent of Grant Thornton LLP.

24             Power  of  Attorney  (included  in  Part  II  under  the  caption
               "Signatures").




                                     II-11
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{"company-data": {"conformed-name": "UNITIL CORP", "cik": "0000755001", "assigned-sic": "4931", "irs-number": "020381573", "state-of-incorporation": "NH", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-42266", "film-number": "679276"}, "business-address": {"street1": "6 LIBERTY LAND WEST", "city": "HAMPTON", "state": "NH", "zip": "03842", "phone": "6037736504"}, "mail-address": {"street1": "6 LIBERTY LAND WEST", "city": "HAMPTON", "state": "NH", "zip": "03842"}}
As filed with the Securities and Exchange Commission on July 26, 2000.

                                                       Registration No. 333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549
                                    --------

                                    FORM S-8

                             REGISTRATION STATEMENT

                                      UNDER

                           THE SECURITIES ACT OF 1933
                                 --------------

                               UNITIL CORPORATION
             (Exact name of registrant as specified in its charter)

         New Hampshire                                         02-0381573
(State or other jurisdiction of                              (I.R.S. Employer
incorporation or organization)                              Identification No.)

             6 Liberty Lane West, Hampton, New Hampshire 03842-1720
           (Address of principal executive office, including zip code)

                               ------------------

                               UNITIL CORPORATION
                    TAX DEFERRED SAVINGS AND INVESTMENT PLAN

                            (Full title of the plan)

                             Anthony J. Baratta, Jr.
                            Senior Vice President and
                             Chief Financial Officer

                               UNITIL CORPORATION
                               6 Liberty Lane West
                        Hampton, New Hampshire 03842-1720
                                 (603) 772-0775
(Name, address, and telephone number, including area code, of agent for service)

                                   Copies to:
                             David S. Balabon, Esq.
                     LEBOEUF, LAMB, GREENE & MACRAE, L.L.P.
                               260 Franklin Street
                           Boston, Massachusetts 02110
                                 (617) 439-9500

                               ------------------

                         CALCULATION OF REGISTRATION FEE
Title of                                Proposed maximum       Proposed maximum
           securities            Amount to be       offering price       aggregate offering
      to be registered 1         registered 2         per share3               price3         Amount of registration fee4

         Common Stock,              150,000            $26.6875              $4,003,125               $1,056.83
         no par value               shares
=========================================================================================================================
================================================================================
1 In addition,  pursuant to Rule 416(c) under the Securities  Act of 1933,  this
Registration  Statement also covers an  indeterminate  amount of interests to be
offered or sold pursuant to the employee benefit plan described herein.

2 In addition,  pursuant to Rule 416(a) under the Securities  Act of 1933,  this
Registration  Statement also covers any  additional  securities to be offered or
issued in connection with a stock split, stock dividend or similar transaction.

3 Estimated  solely for the purpose of calculating the registration fee pursuant
to Rule 457(h) under the  Securities  Act of 1933 on the basis of the average of
the high and low prices of the Common  Stock as reported by the  American  Stock
Exchange  on July 21, 2000 which date is within  five (5)  business  days of the
filing hereof.

4 In accordance with Rule 457(h)(2) no separate fee calculation is made for plan
interests.

================================================================================

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference.
------   ---------------------------------------

     The  following  documents,  which  have  heretofore  been  filed by  Unitil
Corporation (the "Company")  and/or the Unitil  Corporation Tax Deferred Savings
and Investment  Plan (the "Plan") with the  Securities  and Exchange  Commission
(the "Commission")  pursuant to the Securities  Exchange Act of 1934, as amended
(the "Exchange Act"), are hereby  incorporated by reference in this Registration
Statement:

     (a) The  Company's  Annual  Report on Form 10-K for the  fiscal  year ended
December 31, 1999, as amended by Form 10-K/A filed with the  Commission on April
14, 2000.

     (b) The Company's Quarterly Report on Form 10-Q for the quarter ended March
31, 2000.

     (c)  The  description  of  the  Company's  Common  Stock  contained  in the
Company's  Registration  Statement  on Form 8-A  filed  with the  Commission  on
February 8, 1985,  pursuant to Section 12 of the Exchange Act, and any amendment
or  report  filed  with  the   Commission  for  the  purpose  of  updating  such
description.

     (d) The Plan's Annual  Report on Form 11-K for the year ended  December 31,
1999.

     All  documents  subsequently  filed by the  Company  and the Plan  with the
Commission  pursuant to Section 13(a),  13(c),  14 or 15(d) of the Exchange Act,
prior to the  filing of a post-  effective  amendment  that  indicates  that all
securities offered hereby have been sold or that deregisters all securities then
remaining  unsold,  shall be  deemed to be  incorporated  by  reference  in this
Registration  Statement  and to be a part hereof from the date of filing of such
documents.  Any statement  contained in a document  incorporated or deemed to be
incorporated  by reference  herein shall be deemed to be modified or  superseded
for  purposes  of this  Registration  Statement  to the extent  that a statement
contained herein or in any other subsequently filed document that also is deemed
to be  incorporated  by reference  herein modifies or supersedes such statement.
Any such statement so modified or superseded  shall not be deemed,  except as to
modified or superseded, to constitute a part of this Registration Statement.

Item 4.  Description of Securities.
------   -------------------------

         Not applicable.

                                      II-1
Item 5.  Interests of Named Experts and Counsel.
------   --------------------------------------

     Paul K.  Connolly,  Jr., a member of the firm of  LeBoeuf,  Lamb,  Greene &
MacRae,  L.L.P., which is rendering an opinion on the validity of the securities
being registered  hereunder,  owns 2,631 shares of the Company's Common Stock as
of the date of this Registration Statement. Mr. Connolly is a participant in the
Company's Dividend  Reinvestment and Stock Purchase Plan and, as such,  acquires
additional shares of Common Stock at regular intervals.

Item 6.  Indemnification of Directors and Officers.
------   -----------------------------------------

     The Company is organized under the laws of the State of New Hampshire.  The
New Hampshire  Business  Corporation Act (the "Act") provides that a corporation
may indemnify an individual made a party to a proceeding  because he is or was a
director  against  liability  incurred in the  proceeding  if: (1) he  conducted
himself in good faith; and (2) he reasonably believed (i) in the case of conduct
in his official capacity with the corporation,  that his conduct was in its best
interests;  and (ii) in all  other  cases,  that his  conduct  was at least  not
opposed to its best interests;  and (3) in the case of any criminal  proceeding,
he had no reasonable  cause to believe his conduct was  unlawful.  A corporation
may not  indemnify a director (x) in  connection  with a proceeding by or in the
right of the  corporation  in which  the  director  was  adjudged  liable to the
corporation;  or (y) in connection with any other proceeding  charging  improper
personal  benefit  to him,  whether  or not  involving  action  in his  official
capacity, in which he was adjudged liable on the basis that personal benefit was
improperly  received by him. Unless limited by its articles of incorporation,  a
corporation shall indemnify a director or officer who was wholly successful,  on
the merits or  otherwise,  in the  defense of any  proceeding  to which he was a
party  because he is or was a director  or  officer of the  corporation  against
reasonable  expenses  incurred  by him in  connection  with  the  proceeding.  A
corporation  may purchase and maintain  insurance on behalf of an individual who
is or was a director,  officer,  employee, or agent of the corporation,  or who,
while a  director,  officer,  employee  or agent of the  corporation,  is or was
serving at the  request of the  corporation  as a  director,  officer,  partner,
trustee,  employee,  or  agent  of  another  foreign  or  domestic  corporation,
partnership,  joint venture,  trust, employee benefit plan, or other enterprise,
against  liability  asserted  against or  incurred  by him in that  capacity  or
arising from his status as a director,  officer,  employee, or agent, whether or
not the corporation would have power to indemnify him against the same liability
under the Act.

     Article  X of  the  Company's  By-Laws  provides  that  the  Company  shall
indemnify  any person who was or is a party or is threatened to be made a party,
to any  threatened,  pending or completed  action,  suit or proceeding,  whether
civil,  criminal,  administrative  or  investigative,  by reason of the person's
having served as, or by reason of the person's  alleged acts or omissions  while
serving as a  director,  officer,  employee  or agent of the  Company,  or while
serving at the request of the Company as a director,  officer, employee or agent
of another corporation,  partnership,  joint venture, trust or other enterprise,
against expenses,  including attorney's fees, judgments,  fines and amounts paid
in settlement or otherwise actually and reasonably incurred by him in connection
with the action, suit or proceeding,  if the person acted in good faith and in a
manner he reasonably  believed to be in or not opposed to the best  interests of
the Company,  and,  with respect to any criminal  action or  proceeding,  had no
reasonable cause to believe his conduct

                                      II-2
was unlawful,  said  indemnification  to be to the full extent  permitted by law
under  the  circumstances,  including,  without  limitation,  by all  applicable
provisions of the Act. Any  indemnification  under this Article shall be made by
the Company with respect to Directors  or other  persons  after a  determination
that the person to be indemnified  has met the standards of conduct set forth in
the Act, such  determination  to be made by the Board of Directors,  by majority
vote of a quorum,  or by other persons  authorized to make such a  determination
under the Act.

     The right of indemnification  arising under this Article is adopted for the
purpose  of  inducing  persons  to serve and to  continue  to serve the  Company
without  concern that their service may expose them to personal  financial harm.
It shall be broadly construed, applied and implemented in light of this purpose.
It shall  not be  exclusive  of any  other  right to which  any such  person  is
entitled  under  any  agreement,  vote  of  the  stockholders  or the  Board  of
Directors,  statute,  or as a  matter  of law,  or  otherwise,  nor  shall it be
construed to limit or confine in any respect the power of the Board of Directors
to grant indemnity  pursuant to any applicable  statutes or laws of the State of
New  Hampshire.  The  provisions  of this  Article  are  separable,  and, if any
provision or portion hereof shall for any reason be held  inapplicable,  illegal
or  ineffective,  this  shall  not  affect  any other  right of  indemnification
existing  under this Article or  otherwise.  As used herein,  the term  "person"
includes heirs,  executors,  administrators or other legal  representatives.  As
used herein,  the terms  "Director"  and "officer"  include  persons  elected or
appointed as officers by the Board of Directors, persons elected as Directors by
the stockholders or by the Board of Directors,  and persons who serve by vote or
at the  request of the  Company as  directors,  officers  or trustees of another
organization  in which the  Company  has any direct or  indirect  interest  as a
shareholder, creditor or otherwise.

     The Company may purchase and maintain insurance on behalf of any person who
was  or is a  Director,  officer  or  employee  of  the  Company  or  any of its
subsidiaries,  or who was or is  serving  at the  request  of the  Company  as a
fiduciary of any employee benefit plan of the Company or any subsidiary, against
any  liability  asserted  against,  and  incurred  by,  such  person in any such
capacity,  or arising out of such  person's  status as such,  whether or not the
Company  would have the power to indemnify  such person  against such  liability
under the  provisions of the Act. The obligation to indemnify and reimburse such
person under this Article, if applicable,  shall be reduced by the amount of any
such  insurance  proceeds  paid  to  such  person,  or  the  representatives  or
successors of such person.

     The  Company  holds  a  directors  and  officers  liability  and  corporate
indemnification policy to protect itself and its directors,  officers, employees
and agents against any expense,  liability or loss, subject to certain limits in
coverage  and  deductibles,  whether or not the Company  would have the power to
indemnify such person against such expense, liability or loss under the Act.

Item 7.  Exemption from Registration Claimed.
------   -----------------------------------

     Not applicable.

                                      II-3
Item 8.  Exhibits.
------   --------

         Exhibit No.

         4.1        Unitil Corporation Tax Deferred Savings and Investment Plan,
                    as amended and restated and effective as of January 1, 1989.

         4.2        Amendment No. 1 to Unitil  Corporation Tax Deferred  Savings
                    and Investment Plan effective as of July 1, 1996.

         4.3        Amendment No. 2 to Unitil  Corporation Tax Deferred  Savings
                    and Investment Plan effective as of January 1, 1997.

         4.4        Unitil  Corporation Tax Deferred Savings and Investment Plan
                    Trust Agreement.

         4.5        Articles of Incorporation of the Company,  as amended (filed
                    as Exhibit 3.1 to the  Company's  Registration  Statement on
                    Form  S-14,  No.  2-93769,   and   incorporated   herein  by
                    reference).

         4.6        Articles of Amendment to the  Articles of  Incorporation  of
                    the Company  (filed as Exhibit 3.2 to the  Company's  Annual
                    Report on Form 10-K for the fiscal year ended  December  31,
                    1992, and incorporated herein by reference).

         4.7        By-Laws  of  the  Company  (filed  as  Exhibit  4.4  to  the
                    Company's Registration Statement on Form S-8, 333-73327, and
                    incorporated herein by reference).

         5          Opinion of LeBoeuf, Lamb, Greene & MacRae, L.L.P.

         23.1       Consent of LeBoeuf,  Lamb, Greene & MacRae, L.L.P. (included
                    in Exhibit 5).

         23.2       Consent of Grant Thornton LLP.

         24         Power of  Attorney  (included  in Part II under the  caption
                    "Signatures").

     Pursuant  to Item  8(b) of Form  S-8,  the  undersigned  Registrant  hereby
undertakes  that it will  submit or has  submitted  the Plan and any  amendments
thereto to the Internal  Revenue Service ("IRS") in a timely manner and has made
or will make all changes  required by the IRS in order to qualify the Plan under
Section 401 of the Internal Revenue Code of 1986, as amended.

                                      II-4
Item 9.  Undertakings.
------   ------------

     (a) The undersigned Registrant hereby undertakes:

        (1) To file, during any period in which  offers or sales are being made,
a post-effective amendment to this Registration Statement:

                    (i) To include any prospectus  required by Section  10(a)(3)
               of the Securities Act of 1933;

                    (ii) To  reflect  in the  prospectus  any  facts  or  events
               arising after the effective  date of the  Registration  Statement
               (or the most  recent  post-effective  amendment  thereof)  which,
               individually or in the aggregate,  represent a fundamental change
               in the  information  set  forth  in the  Registration  Statement.
               Notwithstanding the foregoing, any increase or decrease in volume
               of  securities  offered (if the total dollar value of  securities
               offered  would not  exceed  that  which was  registered)  and any
               deviation  from  the low or  high  end of the  estimated  maximum
               offering  range may be reflected in the form of prospectus  filed
               with the Commission pursuant to Rule 424(b) if, in the aggregate,
               the changes in volume and price represent no more than 20 percent
               change in the maximum  aggregate  offering price set forth in the
               "Calculation  of   Registration   Fee"  table  in  the  effective
               Registration Statement.

                    (iii) To include any  material  information  with respect to
               the  plan  of  distribution  not  previously   disclosed  in  the
               Registration Statement or any material change to such information
               in the Registration Statement;

provided,  however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the
Registration Statement is on Form S-3, Form S-8 or Form F-3, and the information
required to be included in a  post-effective  amendment by those  paragraphs  is
contained in periodic  reports filed with or furnished to the  Commission by the
Registrant  pursuant to Section 13 or 15(d) of the  Securities  Exchange  Act of
1934 and that are incorporated by reference in the Registration Statement.

        (2) That,  for  the  purpose  of  determining  any  liability  under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new Registration Statement relating to the securities offered therein, and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

        (3) To  remove from registration by means of a post-effective  amendment
any of the securities  being registered that remain unsold at the termination of
the offering.

     (b) The  undersigned  Registrant  hereby  undertakes  that, for purposes of
determining  any liability  under the Securities Act of 1933, each filing of the
Registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Securities  Exchange  Act of 1934  (and,  where  applicable,  each  filing of an
employee  benefit  plan's  annual  report  pursuant  to  Section  15(d)  of  the
Securities  Exchange  Act of 1934)  that is  incorporated  by  reference  in the
Registration

                                      II-5
Statement  shall be deemed to be a new  Registration  Statement  relating to the
securities  offered  therein,  and the offering of such  securities at that time
shall be deemed to be the initial bona fide offering thereof.

     (c) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors,  officers and controlling  persons of
the  Registrant  pursuant  to  the  foregoing  provisions,   or  otherwise,  the
Registrant  has been advised that in the opinion of the  Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore,  unenforceable. In the event that a claim for indemnification
against such  liabilities  (other than the payment by the Registrant of expenses
incurred or paid by a director,  officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director,  officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been  settled by  controlling  precedent,  submit to a court of  appropriate
jurisdiction the question whether such  indemnification  by it is against public
policy as expressed in the Act and will be governed by the final adjudication of
such issue.

                                      II-6
SIGNATURES

     The Registrant. Pursuant to the requirements of the Securities Act of 1933,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the  requirements  for  filing  on  Form  S-8 and has  duly  caused  this
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly  authorized,  in the Town of Hampton,  the State of New Hampshire,  on this
26th day of July, 2000.

                                             UNITIL CORPORATION

                                             By: /s/ Anthony J. Baratta, Jr.
                                                ----------------------------
                                                 Anthony J. Baratta, Jr.
                                                 Senior Vice President and
                                                 Chief Financial Officer

                                      II-7
KNOW ALL  PERSONS  BY THESE  PRESENTS,  that each  person  whose  signature
appears  below  constitutes  and appoints  Anthony J.  Baratta,  Jr. and Mark H.
Collin,   and  each  of  them   individually,   his  or  her  true  and   lawful
attorney-in-fact  and agent with full power of substitution  and  resubstitution
for  him  or her  and in his or her  name,  place  and  stead,  in any  and  all
capacities, to sign any and all amendments (including post-effective amendments)
of and supplements to this Registration Statement and to file the same, with all
exhibits  thereto,  and  other  documents  in  connection  therewith,  with  the
Securities and Exchange Commission, granting unto each such attorney-in-fact and
agent, or his  substitutes,  full power and authority to do and perform each and
every  act and  thing  requisite  and  necessary  to be done  in and  about  the
premises,  to all intents and  purposes and as fully as he or she might or could
do  in   person,   hereby   ratifying   and   confirming   all  that  each  such
attorney-in-fact  and agent, or his substitutes,  may lawfully do or cause to be
done by virtue hereof.

     Pursuant  to  the   requirements  of  the  Securities  Act  of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the date indicated:

Signature                             Title                            Date

/s/ Michael J. Dalton                 Director, President and      July 26, 2000
---------------------                 Chief Operating Officer
Michael J. Dalton

/s/ Robert G. Schoenberger            Director, Chairman of        July 26, 2000
--------------------------            the Board and Chief
Robert G. Schoenberger                Executive Officer

/s/ William E. Aubuchon, III          Director                     July 26, 2000
----------------------------
William E. Aubuchon, III

/s/ Albert H. Elfner, III             Director                     July 26, 2000
-------------------------
Albert H. Elfner, III

/s/ Ross B. George                    Director                     July 26, 2000
------------------
Ross B. George

                                      II-8
Signature                             Title                            Date

/s/ Bruce W. Keough                   Director                     July 26, 2000
-------------------
Bruce W. Keough

/s/ Eben S. Moulton                   Director                     July 26, 2000
-------------------
Eben S. Moulton

/s/ M. Brian O'Shaughnessy            Director                     June 26, 2000
--------------------------
M. Brian O'Shaughnessy

/s/ J. Parker Rice, Jr.               Director                     July 26, 2000
-----------------------
J. Parker Rice, Jr.

/s/ Charles H. Tenney III             Director                     July 26, 2000
-------------------------
Charles H. Tenney III

/s/ Joan D. Wheeler                   Director                     July 26, 2000
-------------------
Joan D. Wheeler

                                      II-9
The Plan.  Pursuant to the  requirements of the Securities Act of 1933, the
trustees (or other persons who administer  the employee  benefit plan) have duly
caused  this  Registration   Statement  to  be  signed  on  its  behalf  by  the
undersigned, thereunto duly authorized, in the Town of Hampton, the State of New
Hampshire, on this 26th day of July, 2000.

                                               By:  Plan Administrator

                                               By:/s/ Mark H. Collin
                                                  ------------------
                                                     Mark H. Collin
                                                     Treasurer and Secretary

                                      II-10
EXHIBIT INDEX

Exhibit
  No.          Title of  Exhibit

4.1            Unitil  Corporation Tax Deferred  Savings and Investment Plan, as
               amended and restated and effective as of January 1, 1989.

4.2            Amendment No. 1 to Unitil  Corporation  Tax Deferred  Savings and
               Investment Plan effective as of July 1, 1996.

4.3            Amendment No. 2 to Unitil  Corporation  Tax Deferred  Savings and
               Investment Plan effective as of January 1, 1997.

4.4            Unitil Corporation Tax Deferred Savings and Investment Plan Trust
               Agreement.

4.5            Articles of  Incorporation  of the Company,  as amended (filed as
               Exhibit 3.1 to the Company's Registration Statement on Form S-14,
               No. 2-93769, and incorporated herein by reference).

4.6            Articles of  Amendment to the  Articles of  Incorporation  of the
               Company  (filed as Exhibit 3.2 to the Company's  Annual Report on
               Form 10-K for the  fiscal  year  ended  December  31,  1992,  and
               incorporated herein by reference).

4.7            By-Laws of the  Company  (filed as Exhibit  4.4 to the  Company's
               Registration   Statement   on  Form  S-8,  No.   333-73327,   and
               incorporated herein by reference).

5              Opinion of LeBoeuf, Lamb, Greene & MacRae, L.L.P.

23.1           Consent of LeBoeuf,  Lamb, Greene & MacRae,  L.L.P.  (included in
               Exhibit 5).

23.2           Consent of Grant Thornton LLP.

24             Power  of  Attorney  (included  in  Part  II  under  the  caption
               "Signatures").

                                     II-11