Sunbury-on-Thames (or commonly Sunbury) is a town on the north bank of the River Thames in the Borough of Spelthorne, approximately 13 mi (21 km) southwest of central London. Historically part of the county of Middlesex, it was transferred to Surrey in 1965. Sunbury adjoins Feltham to the north, Hampton to the east, Ashford to the northwest and Shepperton to the southwest. Walton-on-Thames is to the south, on the opposite bank of the Thames. Sunbury railway station is on the Shepperton branch line. Trains to and from London Waterloo are operated by South Western Railway.