Startforth is a village on the Pennines end of south Teesdale, England. The population of Startforth taken at the 2011 Census was 1,361. It is historically located in the North Riding of Yorkshire, but along with the rest of the former Startforth Rural District, it was transferred to County Durham for administrative and ceremonial purposes on 1 April 1974, under the provisions of the Local Government Act 1972. It is situated south-west of Barnard Castle, north of the River Tees. Located in the village is Deerbolt Prison, a male juvenile's prison and Young Offenders Institution.