Dumbarton is a coastal parish, which lies in West Dunbartonshire Council Area, some 3 miles (5 km) east of Alexandria and 6 miles (10 km) northwest of Clydebank in West Dunbartonshire.
It is located in the old county of Dunbartonshire, which disappeared following the Local Government (Scotland) Act 1974.
The parish has an area of 33.9 sq. km (13.1 sq. miles). Dumbarton has 6 neighbouring parishes; namely Bonhill, Cardross, Drymen, Killearn, Kilmaronock and Old Kilpatrick.