High Quality Content by WIKIPEDIA articles! The Metropolitan Borough of Wirral is a metropolitan borough of Merseyside, North West England, which occupies the northern part of the Wirral Peninsula.The Metropolitan Borough of Wirral has a population of about 311,200 (2006 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 Cheshire West and Chester, in Cheshire..