Orley Farm School is one of the largest coeducational preparatory day schools in the London borough of Harrow, at the foot of Harrow Hill on South Hill Avenue. The school grounds cover 37 acres (150,000 m²). Orley Farm was founded in 1850 as the preparatory school for the nearby Harrow School, but is now a fully private school in its own right and leavers continue to a variety of other private schools.