Its population as of the 2001 census was 8,000,550; the most populous region. The highest point is Walbury Hill in Berkshire at 297m/974 ft. In common usage the area referred to by South East may vary.
Chichester and the nearby Roman villa at Fishbourne, believed to be Cogidubnus' palace, were part of the territory of the Atrebates before the conquest. Cogidubnus may therefore have been an heir of Verica, the Atrebatic king whose overthrow prompted the Roman conquest. After the conquest they were part of the civitas of the Regnenses, which was probably Cogidubnus' kingdom before being incorporated into the Roman province. The public baths, amphitheatre and forum in Silchester were probably built in Cogidubnus' time.