Harrow on the Hill, Great Stanmore, and Little Stanmore (also known as Whitchurch) are the three ancient parishes that form the modern borough. There were consistent boundaries between these areas in the High Middle Ages and the modern era. In 1766, Pinner became independent of Harrow on the Hill, and in 1894 the remaining area was split into four daughter parishes: Harrow Weald, Harrow, Wealdstone and Wembley (the latter is now part of the London Borough of Brent).
As a result of the Middlesex Review Order 1934, Harrow Urban District was formed in 1934 as an urban district in Middlesex, combining Harrow on the Hill Urban District with Wealdstone Urban District and most of Hendon Rural District. Harrow Urban District Council was the local authority.
Upon the incorporation of the urban district as a borough on 4 May 1954, the urban district council became Harrow Borough Council. The 50th anniversary of the incorporation as a borough was celebrated in April 2004, which included a visit from Queen Elizabeth II.
A new London Borough of Harrow was formed in 1965 as a result of the abolishment of the municipal borough, which was transferred to Greater London from Middlesex under the London Government Act 1963.
It is the only London borough to replicate almost exactly the same boundaries as one former district. In 1961, it had a population of 209,080, making it the largest local government district in Middlesex. Despite this, Harrow's boundaries have changed slightly, as part of Elstree was transferred to Hertfordshire (and its district of Hertsmere) on 1 April 1993.
Originally granted in 1938, the coat of arms was granted to Harrow Urban District Council. Supporters of the arms were granted in 1954, when the urban district became a municipal borough. With unaltered boundaries, the municipal borough became the London Borough of Harrow in 1965, and so the council retained its arms.
Harrow Borough F.C. also uses the arms with the motto "Salus Populi Suprema Lex" translating from Latin as "The well-being of the people is the highest law.".
Sport and Leisure
A total of four non-league football clubs are located in the London Borough of Harrow: Barnet F.C., which moved to The Hive Stadium from nearby Barnet in 2013, plays in the National League (division); three non-League clubs play at The Vale, Harrow Borough F.C. plays at Earlsmead Stadium, and Rayners Lane F.C. plays at Tithe Farm Social Club.
The London Borough of Harrow is home to five of the 30 cricket clubs playing in the Middlesex County Cricket League: Harrow St Mary's, Harrow Town, Kenton and Stanmore. Previously, Hatch End Cricket Club played at Shaftesbury Playing Fields, but in 2011, the club moved to Elstree after an arson attack on their clubhouse and a failure to raise funds to build a new one.
London Broncos played at The Hive Stadium in Harrow in 2014 and 2015. They relocated to Ealing from 2016 onwards.