Wallasey, an urban district in the Wirral parliamentary division of Cheshire, England, 2 m. N.W. of Birkenhead, of which it forms a suburb. Pop. (1901) 53,579. The former marshy estuary called Wallasey Pool is occupied by the Great Float, forming an immense dock (see Birkenhead). The church of St Hilary, to which is assigned a foundation in the 10th century, was rebuilt in the 18th century, with the exception of the tower bearing the date 1536. It was gutted by fire in 1857, and the whole was again rebuilt in the Early English style. On the shore of the Irish Sea is Leasowe Castle, once known as Mock-Beggar Hall, and supposed to have been erected by the earls of Derby in the reign of Elizabeth, in order to witness the horse-races held here. Under Wallasey Pool are remains of a submerged forest, in which various animal skeletons have been found.
At the Conquest Wallasey formed part of the possessions of Robert de Rhuddlan, and on his decease became part of the fee of Halton. In the reign of Elizabeth it had a small port, to which there belonged three barques and fourteen men. In 1668 the manor was possessed by the earl of Derby, but various parts afterwards became alienated. For a considerable time the horse-races held on what was then a common had considerable reputation, but they were discontinued in 1760. At these races the duke of Monmouth, son of Charles II., once rode his own horse and won the plate.
