Corsham is a historic market town and civil parish in west Wiltshire, England. It is at the south-eastern edge of the Cotswolds, just off the A4 national route, 28 miles (45 km) southwest of Swindon, 20 miles (32 km) southeast of Bristol, 8 miles (13 km) northeast of Bath and 4 miles (6 km) southwest of Chippenham. The parish includes the villages of Gastard and Neston, which is at the gates of the Neston Park estate.