Lesmahagow is a parish, which lies in South Lanarkshire Council Area, some 6 miles (9 km) north of Douglas and 7 miles (12 km) south of Carluke in South Lanarkshire.
It is located in the old county of Lanarkshire, which disappeared following the Local Government (Scotland) Act 1974.
The parish has an area of 168.1 sq. km (64.9 sq. miles). Lesmahagow has 8 neighbouring parishes; namely Avondale, Carluke, Carmichael, Dalserf, Douglas, Lanark, Muirkirk and Stonehouse.