Greater Manchester spans 496 square miles (1,285 km2). It is landlocked and borders Cheshire (to the south-west and south), Derbyshire (to the south-east), West Yorkshire (to the north-east), Lancashire (to the north) and Merseyside (to the west). There is a mix of high density urban areas, suburbs, semi-rural and rural locations in Greater Manchester, but overwhelmingly the land use is urban. It has a focused central business district, formed by Manchester city centre and the adjoining parts of Salford and Trafford, but Greater Manchester is also a polycentric county with ten metropolitan districts, each of which has at least one major town centre and outlying suburbs. The Greater Manchester Urban Area is the third most populous conurbation in the UK, and spans across most of the county's territory.