Lennox and Addington electoral district was located in the eastern area of Canada West.

[2] Lennox and Addington Counties had been an electoral district in the Legislative Assembly of Upper Canada.

Those boundaries had originally been set by a proclamation of the first Lieutenant Governor of Upper Canada, John Graves Simcoe, in 1792, defining the two separate counties of Addington and Lennox (originally called Lenox): The boundaries had been further defined by a statute of Upper Canada in 1798: Since Lennox and Addington were not changed by the Union Act, those boundaries continued to be used for the new electoral district.

The district of Lennox and Addington was represented by one member in the Legislative Assembly.

[10] This article incorporates text from this source, which is in the public domain: Proclamation, Lieutenant Governor John Graves Simcoe, July 16, 1792 This article incorporates text from this source, which is in the public domain: An act for the better division of this province, SUC 1798, c. 5, s. XX..