Wirral is a metropolitan borough in Merseyside, North West England, which occupies the northern part of the Wirral Peninsula, more commonly known as Wirral. Wirral Metropolitan Borough has a population of about 311,235 (2004 estimate) in an area of 60 square miles (155 km²). It faces Liverpool over the River Mersey to the east, the Irish Sea to the north and the River Dee to the west. To the south it borders the borough of Ellesmere Port and Neston, in Cheshire.