Osterley Park is a large park and one of the largest open spaces in London. In its grounds, there is a large mansion which is often referred to as 'Osterley House'. The park lies between Osterley, Isleworth; Heston, Hounslow; Norwood Green, Southall, Hanwell, Ealing and Brentford, in the London Boroughs of Hounslow and Ealing.