The seat was mostly located in the Clerkenwell district, with a detached portion at Muswell Hill containing about 5% of the population. The two areas were connected for historic reasons. The Social Geography of British Elections 1885-1910, explains that the Knights of St John had once owned more than half of Clerkenwell, including a deer park at Muswell Hill.
In 1889 Clerkenwell was severed from Middlesex to become part of the County of London.
In 1900 the lower tier of local government in London was rationalised. The old local boards and parish vestries were replaced, in the Clerkenwell area, by the Metropolitan Borough of Finsbury. The Muswell Hill area formed part of the Hornsey Urban District, which became the Municipal Borough of Hornsey in 1903.
The local government changes did not affect the parliamentary boundaries until the redistribution of 1918, when the Central division ceased to be a separate constituency.