The riding of Nepean is in the south-west part of Ottawa, and runs from Eagleson Road in the west, to the river in the east, along the train tracks north of Hunt Club, and up to Bankfield Road in the south.

The riding was initially created as Nepean-Carleton in 1976, and was renamed Nepean in 1986. In 1996, it was combined with part of Carleton-Gloucester and Lanark-Carleton and became Nepean-Carleton again. In 2004, the riding lines were redrawn to take in part of eastern Ottawa, up to the 417. The riding boundaries were changed again in 2018 splitting the ridding into two.