Merseyside (/ˈmɜːrzisaɪd/ MUR-zee-syde) is a metropolitan and ceremonial county in North West England, with a population of 1.38 million. It encompasses both banks 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 and sits within the historic counties of Lancashire and Cheshire.