Nepean, Ont, was a city (incorporated from 1978 to 2001) until it and 10 other municipalities were merged into the new city of Ottawa. Nepean was named in honour of Sir Evan Nepean, head of the colonial branch of the British Home Office.

Nepean's first permanent settler came to the area in 1810. However, it was the building of the Rideau Canal that boosted settlement in the township. The first settlers farmed and worked on the lumber drives in the winter. From 1889 to 1950 significant amounts of land from Nepean were annexed by Ottawa. These annexations decreased both the area and population of Nepean. Despite the annexations, growth was not hindered. Nepean became attractive to people seeking a suburban lifestyle, and the community later attracted manufacturing firms in the high technology sector. Six industrial or business parks have been developed, concentrated primarily along the Rideau River. In 2001 Nepean was finally engulfed by its larger neighbour.

Algonquin College of the Applied Arts and Technology has its headquarters in Nepean. The community is also home to the Nepean National Equestrian Park.