Avon Local History and Archaeology - Resource to search for local archaeological and historical societies and events 

English Heritage - Summary of the periods and highlighted sites to visit around the UK

Heritage Gateway - Access to search the Historic Environment Records (HER), formal records of nearly 2/3 of the country's heritage sites

Historic England - Short summaries of historic and prehistoric periods in the UK

Historic England Inspector of Ancient Monuments

Ordinance Survey archaeological maps are interesting and informative, showing ancient features visible in the landscape. - Roman Britain - Ancient Britain

South Gloucestershire county archaeologist

South Gloucestershire archaeological finds officer

South Gloucestershire maps - Know your place contains a range of maps and other resources about the history and archaeology of a number of counties in the south west
Thornbury Museum - A good local museum with lots of information about the area throughout the ages and a specialist archaeology group