Bristol is a city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. The county is in the West of England combined authority area, which includes the Greater Bristol area and nearby places such as Bath. Iron Age hillforts and Roman villas were built near the confluence of the rivers Frome and Avon.