Retford (), also known as East Retford, is a market town in Nottinghamshire, and one of the oldest market towns in England having been granted its first charter in 1105. It lies on the River Idle and the Chesterfield Canal passes through its centre. Retford is 26 miles (42 km) east of Sheffield, 23 miles (37 km) west of Lincoln and 31 miles (50 km) north-east of Nottingham. The population at the 2011 census was 22,013.
The village of Ordsall, west of the River Idle and the former hamlet of Thrumpton are suburbs. It is administered by Bassetlaw District Council, which itself is now a non-constituent partner member of the Sheffield City Region Combined Authority.
In addition to being an ancient market town and infamous Rotten Borough, Retford is known as being at the centre of Nonconformism, with the origins of the Pilgrims, Baptists and Wesleys being in this area.