a county of SW England, situated around the lower Severn valley: contains the Forest of Dean and the main part of the Cotswold Hills: the geographical and ceremonial county includes the unitary authority of South Gloucestershire (part of Avon county from 1974 to 1996). Administrative centre: Gloucester. Pop (excluding South Gloucestershire): 568 500 (2003 est). Area (excluding South Gloucestershire):2643 sq km (1020 sq miles)