This page provides links to other relevant organisations:-

Avon Local History & Archaeology (ALHA).
Bristol Archives (Shared web site)
Bristol Industrial Archaeology Society
British Association for Local History.
Bristol & Gloucester Archaeological Society
Gloucester Archives
Gloucestershire Local History Association
Historical Association  (Click onto Bath, Bristol & Wiltshire branches)
Know Your Place: (Digitised historic maps of Bath, Bristol, NE Somerset, Gloucestershire, Somerset, South Gloucestershire & Wiltshire
National Archives
South Gloucestershire Council (Museums & Heritage)
University of Bristol Department of History
University of the West Of England, Regional History Centre
Wiltshire & Swindon History Centre