Allerdale is a local government district with borough status, in Cumbria, England. It is historically part of the English county of Cumberland. Its council is based in Workington and the borough has a population of 93,492 according to the 2001 census.

The District of Allerdale was formed under the Local Government Act 1972, on 1 April 1974 by the merger of the borough of Workington, the urban districts of Maryport, Cockermouth and Keswick; and the rural districts of Cockermouth and Wigton. In 1995 Allerdale was granted borough status.

The name derives from the ancient region of Allerdale, represented latterly by the two wards of Cumberland, called Allerdale above Derwent and Allerdale below Derwent.

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