[1] The Union Act provided that the pre-existing electoral boundaries of Upper Canada would continue to be used in the new Parliament, unless altered by the Union Act itself.

[2] Wentworth county had been an electoral district in the Legislative Assembly of Upper Canada,[3] and its boundaries were not altered by the Union Act.

Those boundaries had originally been set by statute in 1816, when Wentworth county was created as a separate county in the new district of Gore, carved out of the existing Niagara and Home districts.

Wentworth country was defined to include: That the township of Saltfleet, Barton, Benbrook, Glanford, Ancaster and the Beach between Burlington Bay and Lake Ontario, and the Promontory near Coot's Paradise, and so much of the County of Haldimand as lies between Dundas Street and the Onondaga village, commonly called Bear's Foot, including said village,shall from henceforth form and be called the County of Wentworth...[4]Since Wentworth was not changed by the Union Act, those boundaries continued to be used for the new electoral district.

Wentworth electoral district was abolished in 1853, when there was a major redistribution of seats in the Legislative Assembly.