London Borough of Harrow: History
The area of the modern borough broadly corresponds to the three ancient parishes of Harrow on the Hill, Great Stanmore and Little Stanmore (also known as Whitchurch), all of which were historically in the county of Middlesex. Harrow on the Hill was the largest of the three parishes. Pinner was a chapelry of Harrow on the Hill until 1766 when it was made a separate parish.
The central part of the parish of Harrow on the Hill was made a local board district in 1850, with an elected board overseeing public health and responsible for the provision of infrastructure. The local board district covered the original hilltop village and the adjoining hamlets of Roxeth, Sudbury and Greenhill. Greenhill subsequently developed into the modern town centre of Harrow following the opening of Harrow-on-the-Hill station there in 1880.
Such districts were reconstituted as urban districts under the Local Government Act 1894, which also said that parishes could no longer straddle district boundaries. The parts of the old parish of Harrow on the Hill outside the urban district were therefore split into three new parishes called Harrow Weald, Wealdstone and Wembley (the latter now part of the London Borough of Brent). Wealdstone and Wembley were both made into urban districts at the same time.
The urban district was significantly enlarged by the Middlesex Review Order 1934 to take in the neighbouring urban district of Wealdstone and the parishes of Harrow Weald, Pinner, Great Stanmore and Little Stanmore. The urban district was renamed from 'Harrow on the Hill' to just 'Harrow' as part of the 1934 expansion. Harrow Urban District was incorporated as a municipal borough on 4 May 1954. At the 1961 census, the borough had a population of 209,080, making it the most populous local government district in the administrative county of Middlesex.
In 1965 the borough was transferred from Middlesex to Greater London under the London Government Act 1963. It kept the same boundaries, but was renamed the London Borough of Harrow, becoming one of the 32 London Boroughs. It was the only London borough which comprised a single pre-1965 district with no changes to its boundaries. There has since been an adjustment to the borough's northern boundary, where the village of Elstree straddled Harrow and Hertfordshire; on 1 April 1993 Elstree was placed entirely in Hertfordshire (and its district of Hertsmere).