A 2011 census recorded just 680 people living in the town.
Clun takes its name from the river upon which it stands. The name derives from an earlier Colunwy and shares its very early British root with the Colne rivers, in Lancashire and Essex, each of which has a town of the same name on its banks.
The A488 and B4368 roads cross in the town. Craven Arms, Bishop's Castle (6 miles (10 km) to the north) and Ludlow are the neighbouring Shropshire towns, and Knighton, which is in Powys, Wales, is 7 miles (11 km) to the south.