Merseyside ( MUR-zee-syde) is a metropolitan county in North West England, with a population of 1.38 million. It encompasses the metropolitan area centred on both banks of the lower reaches of the Mersey Estuary and comprises five metropolitan boroughs: Knowsley, St Helens, Sefton, Wirral, and the city of Liverpool. Merseyside, which was created on 1 April 1974 as a result of the Local Government Act 1972, takes its name from the River Mersey.
Merseyside spans 249 square miles (645 km2) of land which border Lancashire (to the north-east), Greater Manchester (to the east), Cheshire (to the south and south-east) and the Irish Sea to the west. North Wales is across the Dee Estuary. There is a mix of high density urban areas, suburbs, semi-rural and rural locations in Merseyside, but overwhelmingly the land use is urban. It has a focused central business district, formed by Liverpool City Centre, but Merseyside is also a polycentric county with five metropolitan districts, each of which has at least one major town centre and outlying suburbs. The Liverpool Urban Area is the fifth most populous conurbation in England, and dominates the geographic centre of the county, while the smaller Birkenhead Urban Area dominates the Wirral Peninsula in the south.