Although the city of Peterborough (a
municipal borough until 1974) in the east of England was
traditionally within the county of Northamptonshire, it and the
surrounding localities, known as the Soke of Peterborough,
became an administrative county in its own right in 1899. From
1965 to 1974, this was merged with Huntingdonshire to form the
county of Peterborough and Huntingdonshire. In 1974, the
area (with similar, but not identical, boundaries to the Soke)
became the local government district of Peterborough within the
county of Cambridgeshire, until 1998, when it became a unitary
authority, remaining within the ceremonial county of
Cambridgeshire.

