Many counties are named after their principal town, and the expected form here would be Durhamshire. The county is commonly known as County Durham but was officially named Durham until at least 1997. The structural change legislation in 2009, however, referred to the county of County Durham. The former postal county was known as "County Durham" to distinguish it from the post town of Durham. Durham is the only English county name to be prefixed with "County" in common usage - a practice more common in Ireland.
The ceremonial county of Durham is administered by four unitary authorities. The ceremonial county has no administrative function, but remains the area to which a Lord-Lieutenant and High Sheriff are appointed.
County Durham (governed by Durham County Council). The unitary district was formed on 1 April 2009 replacing the previous two-tier system of a county council providing strategic services and seven district councils providing more local facilities. It has 126 councillors. The seven districts abolished were:
Chester-le-Street, including the Lumley, Pelton and Sacriston areas
Derwentside, including Consett and Stanley
City of Durham, including Durham city and the surrounding areas
Easington, including Seaham and the new town of Peterlee
Borough of Sedgefield, including Spennymoor and Newton Aycliffe
Teesdale, including Barnard Castle and the villages of Teesdale
Wear Valley, including Bishop Auckland, Crook, Willington, Hunwick, and the villages along Weardale
The Borough of Darlington: previous to 1 April 1997 the borough came under the control of Durham County Council.
The Borough of Hartlepool: Until 1 April 1996 the borough was one of four districts in the County of Cleveland.
The part of the Borough of Stockton-on-Tees that is north of the centre of the River Tees. Stockton was also part of Cleveland until 1996. The remainder of the borough is part of the ceremonial county of North Yorkshire.