Lucan is a suburban town to the west of Dublin city, in the administrative county of South Dublin and is situated some 16 km from the capital's city centre. The town lies at the confluence of the River Liffey and the River Griffeen, its tributary. The picturesque old town retains its character, despite hosting ever-expanding areas of new housing that are essentially overspill developments for nearby Dublin. These new areas lead east from the town towards the Liffey Valley Shopping Centre and southeast towards Clondalkin.