The Borough of Eastleigh is a local government district and borough in Hampshire, England, bordering the unitary authority of Southampton, Test Valley, the City of Winchester and the Borough of Fareham. Eastleigh is separated from the New Forest by Southampton Water. Water bounds much of the borough, with Southampton Water and the River Hamble bordering the east and southwest of the district. The built-up nature of neighbouring Southampton and the urban area around the town of Eastleigh contrast with the rural nature of much of the borough, which lies within the Hampshire Basin.