Isleworth is a suburb located in the London Borough of Hounslow alongside the River Thames in West London. Isleworth's relatively small river frontage is dominated by Isleworth Ait. The River Crane flows into the Thames to the south of Isleworth Ait. The Crane's distributary, the Duke of Northumberland's River, also flows into the Thames to the west of Isleworth Ait. By 1965, urban London had further expanded and almost all of the original area was incorporated into Greater London. Middlesex is still used informally as an area name and may be included in some postal addresses.