The Birket is a tributary of the River Mersey, on the Wirral, Merseyside. The watercourse starts as lowland field drainage south of Hoylake and flows along to the south of Meols. Arrowe Brook joins at Moreton, and the Fender joins at Leasowe. The Birket discharges into the West Float at the site of the former Wallasey Pool. It is about 8 miles (13 km) long.