We have Niagara West constituency https://www.openstreetmap.org/relation/13095587 mapped as following the St. Catharines-Lincoln municipal border, however according to Elections Canada https://www.elections.ca/Scripts/vis/Map?L=e&ED=35068&EV=99&EV_TYPE=6&PROV=ON&PROVID=35&QID=-1&PAGEID=27 it also includes a part of St. Catharines around here:

"Consisting of that part of the Regional Municipality of Niagara comprised of:

    (a) the towns of Grimsby, Lincoln and Pelham;
    (b) the townships of West Lincoln and Wainfleet; and
    (c) that part of the City of St. Catharines lying westerly of a line described as follows: commencing at the intersection of the northerly limit of said city with the production of Courtleigh Road; thence southerly along said production, Courtleigh Road, and Third Louth Street to Queen Elizabeth Way; thence easterly along Queen Elizabeth Way to Highway No. 406; thence generally southerly along said highway to First Louth Street; thence southerly along said street to the southerly limit of said city."