THORNBURY, a market-town of England, Gloucestershire, 3 miles from the estuary of the Severn, and 11 N.E. of Bristol. It has a large parish church, in the later English style, with a lofty and richly adorned tower, places of worship for Wesleyans, Independents, Baptists, and Quakers, several schools, alms-houses, and other charitable institutions. In the neighbourhood are the ruins of Thornbury Castle. Pop. of the parish, 4614; of the town, 1470.