Wirral, metropolitan borough, metropolitan county of Merseyside, historic county of Cheshire, northwestern England. It occupies the major portion of the Wirral peninsula, which is bounded by the River Mersey, the Irish Sea, and the River Dee.
Wirral was almost all an agricultural area until the early 19th century, but, with the growth of Liverpool, parts of the peninsula became desirable residential areas for Liverpool businessmen. In 1824 William Laird founded the shipyards at Birkenhead and laid out the town on a grid pattern with Hamilton Square as the focus. Later in the century the Birkenhead docks attracted trade as a commercial port.
Ferries, road tunnels, and a rail tunnel across the Mersey estuary connect Wirral with the city of Liverpool and the rest of Merseyside. Urban, industrial, and commercial development is concentrated on the northeastern side of the peninsula, along the Mersey, while much of the rest of the borough contains a mix of suburban development, villages, and rich agricultural land. The coastal strip from New Brighton to West Kirby is a recreational area, and the Royal Liverpool Golf Club is at Hoylake. Industries include flour milling, the manufacture of margarine and pharmaceuticals, and marine engineering. The long-established Unilever soap works at Port Sunlight adjoin a model garden village created for employees by the first Lord Leverhulme. Area 61 square miles (158 square km). Pop. (2001) 312,293; (2011) 319,783.