Killearn is a parish, which lies in Stirling Council Area, some 9 miles (15 km) north of Clydebank and 10 miles (16 km) east of Alexandria in West Dunbartonshire.
It is located in the old county of Stirlingshire, which disappeared following the Local Government (Scotland) Act 1974.
The parish has an area of 62.5 sq. km (24.1 sq. miles). Killearn has 8 neighbouring parishes; namely Balfron, Campsie, Drymen, Dumbarton, Fintry, New Kilpatrick, Old Kilpatrick and Strathblane.