Teesdale was, from 1974 to 2009, a local government district in County Durham, England. Its council was based in Barnard Castle and it was named after the valley of the River Tees. That part of the district south of the River Tees is historically part of the North Riding of Yorkshire, and made up Startforth Rural District before the Local Government Act 1972 came into effect in 1974. The other predecessors to the district were Barnard Castle urban district and Barnard Castle Rural District. Much of the area had before 1894 constituted a single Teesdale rural sanitary district.