Stoke Newington, or Stoke Newington St. Mary, was one of the ancient parishes of Middlesex, England. In 1889 it was transferred to the newly-created County of London and in 1900 became Stoke Newington Metropolitan Borough. Stoke Newington Metropolitan Borough was abolished in 1965, becoming part of the London Borough of Hackney in Greater London, England.
Metropolitan Borough of Stoke Newington
Under the Metropolis Management Act 1855 Stoke Newington had been grouped with the neighbouring parish of Hackney under the administration of the Hackney District Board of Works. The union with Hackney was very unpopular with the inhabitants of Stoke Newington, and following unsuccessful attempts to end it in 1864, 1880 and 1890, the parish regained independence in 1894. Stoke Newington Vestry consisted of 60 vestrymen, elected from five wards.
South Hornsey formed the southern part of the parish of Hornsey, consisting of the Brownswood Park area south of Finsbury Park, part of Clissold Park and two detached areas entirely surrounded by the parish of Stoke Newington. The exclaves of South Hornsey effectively cut off the south-eastern section of Stoke Newington from the rest of the parish. A local board was formed to govern the area in 1867, becoming an urban district under the Local Government Act 1894.
The London Government Act 1899 provided that the County of London should be divided into metropolitan boroughs. The new authorities were to based on existing parishes with simplified boundaries. It was intended that each borough would have a population of between 100,000 and 400,000 inhabitants. Where an area fell below the threshold of 100,000 inhabitants, it might still be constituted a borough if it had a rateable value (property tax assessment) exceeding £500,000.
Stoke Newington did not wish to merge with Hackney and thus the decision was made to ally the bulk of South Hornsey, with a population about 20,000, with Stoke Newington. This still created a borough of only about 50,000 inhabitants, but the population in the area was rapidly increasing.
The existing parish boundaries frequently divided houses or related to field boundaries that had disappeared with the urbanisation of the area. The commissioners realigned the boundary lines so that for the most part they ran down the centre of roads, railways or watercourses.
To the north, the borough had a boundary with Middlesex, marked by the course of the New River and the Seven Sisters Road. To the west and south was the Metropolitan Borough of Islington, and to the east and northeast was the Metropolitan Borough of Hackney. (A more definite delineation of these boundaries can be found in Wikipedia.
Stoke Newington did not merge with Hackney until 1965 when the two metropolitan boroughs, along with the Metropolitan Borough of Shoreditch were abolished and the area became the London Borough of Hackney in Greater London.
For more information, see the EN Wikipedia article Stoke Newington. There is a long "History" section covering the 11th to the 21st century.