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<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;border-bottom:solid 2.25pt;padding-bottom:1;padding-top:0;'><font size=5>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font SIZE=5>UNITED STATES</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font SIZE=5>SECURITIES AND EXCHANGE COMMISSION</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=2>Washington, D.C. 20549</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=3>___________</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=3>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font SIZE=5>FORM 8-K</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=3>____________</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=3>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font SIZE=2>CURRENT REPORT</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=2>PURSUANT TO SECTION 13 OR 15(d) OF THE</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font SIZE=2>SECURITIES EXCHANGE ACT OF 1934</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=3>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=2>Date of Report (Date of earliest event reported) August 28, 2007</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=3>____________</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=3>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font SIZE=5>BLACK HILLS CORPORATION</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=2>(Exact name of registrant as specified in its charter)</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=3>____________</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=3>&nbsp;</font></p>


<table border="0" cellspacing=0 cellpadding=0 width="93%" style='margin-left:23.4pt;border-collapse:collapse'>
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        <td  colspan="4" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>South Dakota</font></b><b></b></p> </td> </tr>
    <tr >
        <td  colspan="4" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>(State or other jurisdiction of incorporation)</font></b><b></b></p> </td> </tr>
    <tr >
        <td width="162" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>001-31303</font></b><b></b></p> </td>
        <td width="234" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b>&nbsp;</b></p> </td>
        <td  colspan="2" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>46-0458824</font></b><b></b></p> </td> </tr>
    <tr >
        <td width="162" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>(Commission File Number)</font></b><b></b></p> </td>
        <td width="234" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b>&nbsp;</b></p> </td>
        <td  colspan="2" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>(IRS Employer Identification No.)</font></b><b></b></p> </td> </tr>
    <tr >
        <td width="162" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b>&nbsp;</b></p> </td>
        <td width="234" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b>&nbsp;</b></p> </td>
        <td  colspan="2" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b>&nbsp;</b></p> </td> </tr>
    <tr >
        <td  colspan="2" rowspan=2 valign=top style='padding: 0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><b><font size=2>625 Ninth Street, PO Box 1400 </font></b></p>
<p style='margin-left:12.6pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><b><font size=2>Rapid City, South Dakota</font></b></p>
<p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><b><font size=2>(Address of principal executive offices)</font></b><b></b></p> </td>
        <td  colspan="2" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>57709-1400</font></b><b></b></p> </td> </tr>
    <tr >
        <td  colspan="2" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>(Zip Code)</font></b><b></b></p> </td> </tr>
    <tr >
        <td  colspan="4" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>605.721.1700</font></b><b></b></p> </td> </tr>
    <tr >
        <td  colspan="4" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>(Registrant&#146;s telephone number, including area code)</font></b><b></b></p> </td> </tr>
    <tr >
        <td width="162" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b>&nbsp;</b></p> </td>
        <td  colspan="2" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b>&nbsp;</b></p> </td>
        <td width="186" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b>&nbsp;</b></p> </td> </tr>
    <tr >
        <td  colspan="4" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>Not Applicable</font></b><b></b></p> </td> </tr>
    <tr >
        <td  colspan="4" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:center;margin-top:0pt;margin-bottom:0pt'><b><font size=2>(Former name or former address, if changed since last report)</font></b><b></b></p> </td> </tr>
    <tr>
        <td width="162" ></td>

        <td width="234" ></td>

        <td width="12" ></td>

        <td width="186" ></td> </tr> </table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=3>____________</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt; text-indent:0.5in;text-align:left;'><font size=2>Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (</font><i><font size=2>see</font></i><font size=2> General Instruction A.2. below):</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


<table border="0" cellspacing=0 cellpadding=0 width="452" style='margin-left:.5in;border-collapse:collapse'>
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            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><img src="ballot.jpg"><font size=1>&nbsp;&nbsp;Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)</font></p> </td> </tr></table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


<table border="0" cellspacing=0 cellpadding=0 width="452" style='margin-left:.5in;border-collapse:collapse'>
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            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><img src="ballot.jpg"><font size=1>&nbsp;&nbsp;Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)</font></p> </td> </tr></table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


<table border="0" cellspacing=0 cellpadding=0 width="559" style='margin-left:.5in;border-collapse:collapse'>
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        <td width="559" valign=top >
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><img src="ballot.jpg"><font size=1>&nbsp;&nbsp;Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))</font></p> </td> </tr></table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


<table border="0" cellspacing=0 cellpadding=0 width="556" style='margin-left:.5in;border-collapse:collapse'>
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            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><img src="ballot.jpg"><font size=1>&nbsp;&nbsp;Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))</font></p> </td> </tr></table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;border-bottom:solid 2.25pt;padding-bottom:1;padding-top:0;'><font size=5>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=2>1</font></p>

<p style='page-break-before:always'></p>
<pAGE>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><b><font size=2>Item 8.01 Other Events</font></b></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt; text-indent:0.54in;text-align:left;'><font size=2>On August 28, 2007, the Registrant issued a press release jointly with Aquila, Inc. announcing that they have received antitrust clearance from the Federal Trade Commission under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, in connection with the previously announced agreement for the Registrant to acquire Aquila&#146;s electric generating and distribution properties in Colorado and its natural gas distribution properties in Colorado, Iowa, Kansas and Nebraska.  </font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt; text-indent:0.5in;text-align:left;'><font size=2>In April 2007, Aquila and the Registrant filed the requisite state regulatory applications regarding the proposed transaction, including regulatory applications in Colorado, Iowa, Kansas and Nebraska which are still pending.  </font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt; text-indent:0.5in;text-align:left;'><font size=2>The press release is attached as Exhibit 99 to this Form 8-K.</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


<table border="0" cellspacing=0 cellpadding=0 width="349" style='border-collapse:collapse'>
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            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><b><font size=2>Item 9.01</font></b><font size=2>&nbsp;&nbsp;</font></p> </td>
        <td  colspan="3" valign=top style='padding:5.0pt 0in 5.0pt 0in'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><b><font size=2>Financial Statements and Exhibits</font></b></p> </td>
        <td  width="8">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td> </tr>
    <tr >
        <td  width="24">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td>
        <td width="48" valign=top style='padding:5.0pt 0in 5.0pt 0in'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>(d)</font></p> </td>
        <td  colspan="3" valign=top style='padding:5.0pt 0in 5.0pt 0in'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Exhibits</font></p> </td>
        <td   colspan="2">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td> </tr>
    <tr >
        <td   colspan="2">
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></td>
        <td  colspan="2" valign=top style='padding:5.0pt 0in 5.0pt 0in'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>99</font></p> </td>
        <td  colspan="3" valign=top style='padding:5.0pt 0in 5.0pt 0in'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Press release dated August 28, 2007.</font></p> </td> </tr>
    <tr>
        <td width="24" ></td>

        <td width="48" ></td>

        <td width="16" ></td>

        <td width="8" ></td>

        <td width="48" ></td>

        <td width="197" ></td>

        <td width="8" ></td> </tr> </table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'>
</p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=2>2</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style='page-break-before:always'></p>
<pAGE>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><u><font SIZE=2>SIGNATURES</font></u></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt; text-indent:0.54in;text-align:left;'><font size=2>Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


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            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font SIZE=2>BLACK HILLS CORPORATION</font></p> </td> </tr>
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        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td> </tr>
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        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td> </tr>
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        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>By:&nbsp;&nbsp;</font><u><font size=2>/s/ Mark T. Thies</font></u>                                                                                                                   </p> </td> </tr>
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        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:21.0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Mark T. Thies</font></p> </td> </tr>
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        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:21.75pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Executive Vice President</font></p> </td> </tr>
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        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:26.25pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>and Chief Financial Officer</font></p> </td> </tr>
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        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td> </tr>
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        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Date:&nbsp;&nbsp;August 29, 2007</font></p> </td>
        <td width="319" valign=top style='padding:0in 5.4pt 0in 5.4pt'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=1>&nbsp;</font></p> </td> </tr></table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'>
</p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=2>3</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style='page-break-before:always'></p>
<pAGE>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><b><font size=2>Exhibit Index</font></b></p>

<p style=' margin-bottom:0pt; margin-top:5pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:5pt; margin-top:5pt;text-align:left;'><u><font size=2>Exhibit #</font></u></p>


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        <td width="96" valign=top style='padding:5.0pt 0in 5.0pt 0in'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>99</font></p> </td>
        <td width="253" valign=top style='padding:5.0pt 0in 5.0pt 0in'>
            <p style='margin-left:0pt;text-indent:0pt;text-align:left;margin-top:0pt;margin-bottom:0pt'><font size=2>Press release dated August 28, 2007.</font></p> </td> </tr></table>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:center;'><font size=2>4</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>


<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>

<p style=' margin-bottom:0pt; margin-top:0pt;text-align:left;'><font size=2>&nbsp;</font></p>



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{"company-data": {"conformed-name": "BLACK HILLS CORP /SD/", "cik": "0001130464", "assigned-sic": "4911", "irs-number": "460458824", "state-of-incorporation": "SD", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "001-31303", "film-number": "071087612"}, "business-address": {"street1": "625 9TH STREET", "street2": "PO BOX 1400", "city": "RAPID CITY", "state": "SD", "zip": "57709", "phone": "6057212343"}, "mail-address": {"street1": "625 9TH STREET", "street2": "PO BOX 1400", "city": "RAPID", "state": "SD", "zip": "57709"}, "former-company": {"former-conformed-name": "BLACK HILLS HOLDING CORP", "date-changed": "20001222"}}
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
___________
FORM 8-K
____________
CURRENT REPORT
PURSUANT TO SECTION 13 OR 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934
Date of Report (Date of earliest event reported) August 28, 2007
____________
BLACK HILLS CORPORATION
(Exact name of registrant as specified in its charter)
____________
South Dakota
(State or other jurisdiction of incorporation)
001-31303
46-0458824
(Commission File Number)
(IRS Employer Identification No.)
625 Ninth Street, PO Box 1400
Rapid City, South Dakota
(Address of principal executive offices)
57709-1400
(Zip Code)
605.721.1700
(Registrant's telephone number, including area code)
Not Applicable
(Former name or former address, if changed since last report)
____________
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (
see
General Instruction A.2. below):
Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
1
Item 8.01 Other Events
On August 28, 2007, the Registrant issued a press release jointly with Aquila, Inc. announcing that they have received antitrust clearance from the Federal Trade Commission under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, in connection with the previously announced agreement for the Registrant to acquire Aquila's electric generating and distribution properties in Colorado and its natural gas distribution properties in Colorado, Iowa, Kansas and Nebraska.
In April 2007, Aquila and the Registrant filed the requisite state regulatory applications regarding the proposed transaction, including regulatory applications in Colorado, Iowa, Kansas and Nebraska which are still pending.
The press release is attached as Exhibit 99 to this Form 8-K.
Item 9.01
Financial Statements and Exhibits
(d)
Exhibits
99
Press release dated August 28, 2007.
2
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
BLACK HILLS CORPORATION
By:
/s/ Mark T. Thies
Mark T. Thies
Executive Vice President
and Chief Financial Officer
Date:  August 29, 2007
3
Exhibit Index
Exhibit #
99
Press release dated August 28, 2007.
4