Harrow on the Hill or Harrow-on-the-Hill is a locality and historic village in the borough of Harrow in Greater London, England. The name refers to Harrow Hill, 408 feet (124 m), and is located some half a mile south of the modern town of Harrow. The village dates back to early medieval times, built around the 11th-century St Mary's Church, and is the location of Harrow, St Dominic's and John Lyon schools.

The London Borough of Harrow is a London borough in northwest London, England; it forms part of Outer London. It borders four other London boroughs – Barnet to the east of ancient Watling Street, Brent to the southeast, Ealing to the south and Hillingdon to the west – plus the Hertfordshire districts of Three Rivers and Hertsmere to the north. The local authority is Harrow London Borough Council. The London borough was formed in 1965, based on boundaries that had been established in 1934. The borough is made up of three towns: Harrow, Pinner and Stanmore, but also includes western parts of Edgware.