The station was opened as "Harrow" on 2 August 1880, when the Metropolitan Railway was extended from its previous terminus at Willesden Green. Its name was changed to "Harrow-on-the-Hill" on 1 June 1894. Like a number of other Underground stations the name is an example of marketing rather than precision; in this case the town "proper" of the same name is at the top of Harrow Hill while the station is located in Greenhill to the North of Harrow Hill which has become the main shopping area in this part of the Borough of Harrow. Had the governors of Harrow School not made objections during the planning stage it is possible that the Metropolitan Railway might have followed a different route taking it closer to the town centre on the hill. The station is at the heart of Metro-land.
The station building is above ground with the six platforms in a cutting. Two (on the South side) are used by NR services and the other four by the Metropolitan line; the NR platforms are electrified with the LU system (normal services are operated by diesel trains) and incoming LU trains on some routes can be diverted into them should this be necessary during closures of tracks in the area. The station has two entrances, one on Station Approach (leading to Lowlands Road and Harrow Hill) and one on College Road (for the adjacent Harrow Bus Station and the main shopping area). The TfL publication "Tube Access Guide" dated July 2006 indicates this station as having "Connection only between fast, semi-fast and "all stations" Metropolitan line services" (NB-without lifts there will only be step-free interchange between Metropolitan line trains travelling in the same direction) and "Entry and exit not accessible" (see station description above). The Lowlands Road entrance has the fewer steps. The Station is popular as a through route, as it is possible to walk from one entrance to the other without passing through the ticket barrier. The station has toilets, cash machines, Euro cash machines, wi-fi, a bridge, a car park and a waiting room.
Connections: Buses go from Harrow as far afield Watford, Edgware, Wembley, Heathrow Airport, Ruislip, Northolt, Greenford, Charing Cross (Night Bus), Bushey Heath and Northwood.