Sedgefield is a local government district and borough in County Durham, in north-east England. It has a population of about 87,000 (2001 UK census). It is named after Sedgefield; but its largest town is Newton Aycliffe. Other places include Shildon, and Spennymoor. It is represented in Parliament by Tony Blair.
The borough was formed in 1974 by the merger of Sedgefield Rural District , Spennymoor Urban District , Shildon Urban District and part of Darlington Rural District .