Nepean was a municipality adjacent to Ottawa, Ontario, Canada until it was amalgamated with the 10 other municipalities that formed the Regional Municipality of Ottawa Carleton in 2001 to become the new city of Ottawa. However Nepean as a sense of community still exists for its residents.

As a suburban bedroom community, Nepean had been quite distinct from the old city of Ottawa and the regional government of Ottawa-Carleton. Nepean's policies of fiscal prudence contrasted with the fiscal philosophies of the other municipalities in the area. The city entered amalgamation with a large fiscal surplus and a record of tax restraint which was in sharp contrast to the large debt burden of the city of Ottawa and the Regional Municipality of Ottawa-Carleton.

Nepean was incorporated as a township in 1850 and was incorporated as a city in 1978. The geographic boundaries of Nepean changed considerably over this time; the original town hall of the township of Nepean was located in Westboro, which was annexed in 1949 by the city of Ottawa. Nepean's centre then moved to the community of Bells Corners . In the 1950 and 1960s, Nepean's urban area began to expand in previous rural areas in such areas as Centrepointe in the east, and Barrhaven in the south.

Prior to its forced amalgamation with 10 other municipalities into the new city of Ottawa in 2001, the population of Nepean was 124,878.