In 1882, the East Riding of the county of Middlesex it was defined as consisting of the townships of London, West Nissouri, North Dorchester and South Dorchester, the town of London East and the villages of London West and Springfield.

In 1903, the east riding was defined to consist of the townships of Dorchester North, London, Nissouri West and Westminster.

In 1947, it was redefined to consist of the townships of North Dorchester, London, West Nissouri and Westminster, and the eastern part of the City of London.

In 1952, it was redefined to consist of the Townships of Dorchester North, Nissouri West, Westminster, the eastern part of the Township of London, and the eastern part of the City of London.

This riding elected the following members of the House of Commons of Canada: On Mr. Willson being unseated on petition, 15 December 1874: On election being declared void, 21 January 1892: On Mr. Elson's death, 11 June 1913: