The Keep, Dorchester is part of the former county barracks of the 39th Regiment of Foot and the 75th Regiment of Foot. The barracks were built in about 1880 and housed various regiments as units were amalgamated. It ceased to be used in 1958 and most of the site was redeveloped in the 1960s, but the keep remained in Ministry of Defence hands and is now used as a regimental museum. It is a Grade II listed building.