The Wirral Peninsula, known locally as the Wirral, is a peninsula in North West England. The roughly rectangular peninsula is about 15 miles (24 km) long and 7 miles (11 km) wide, and is bounded by the Dee Estuary to the west, the Mersey Estuary to the east, and Liverpool Bay to the north.

The Metropolitan Borough of Wirral is a metropolitan borough of Merseyside, in North West England. It has a population of 322,453 (2022), and encompasses 62 square miles (161 km2) of the northern part of the Wirral Peninsula. Major settlements include Birkenhead, Wallasey, Bebington, Heswall, Hoylake and West Kirby. Wirral is England's westernmost metropolitan borough, faced by the city of Liverpool to the northeast over the River Mersey.