Isleworth is a small town of Saxon origin sited within the London Borough of Hounslow in west London, England. It lies immediately east of the town of Hounslow and west of the River Thames and its tributary the River Crane. Isleworth's original area of settlement, alongside the Thames, is known as 'Old Isleworth'. The north-west corner of the town, bordering on Osterley to the north and Lampton to the west, is known as 'Spring Grove'.