A Vision of Britain through Time provides the following description of Thornton from John Marius Wilson's Imperial Gazetteer of England and Wales of 1870-72:
Thornton was a township in Norhamshire within the county of Durham until 1844, subsequently in Northumberland. It became a separate civil parish in 1866. From 1894 until 1955 it was part of Norham and Islandshires Rural District. In 1955 it was abolished and absorbed into the neighbouring parish of Shoreswood.