Warrington, unitary authority, north-western England, on the River Mersey and the Manchester Ship Canal. The town of Warrington and its surrounding area left the county of Cheshire on April 1, 1998, to become a unitary authority. The new administrative body is responsible for the provision of all local government services, including those previously provided by the county. Although administered separately, Warrington, like the unitary authority of Halton, remains geographically part of Cheshire.

The borough includes the town of Warrington (the administrative centre) and several neighbouring areas, including Risley, Great Sankey, Burtonwood, Appleton, Grappenhall, Penketh, and Stockton Heath. Population 191,084 (2001).