Gloucestershire Constabulary is the territorial police force responsible for policing the non-metropolitan county of Gloucestershire in England. The force formerly covered the area of South Gloucestershire, however this was transformed to the newly formed Avon and Somerset Constabulary in 1974. The force serves 637,000 people over an area of 1,024 square miles (2,650 km2). and covers a number of royal residences, as well as Cheltenham Racecourse and the headquarters of GCHQ.