Birkenhead, a market-town, seaport, municipal, parliamentary, and county borough of Cheshire, lies opposite Liverpool, on the left bank of the Mersey. Birkenhead owes its origin to the Benedictine Priory of Byrkhed, founded in the 11th century. The crypt and other portions of the priory still remain. Birkenhead has only of late risen from comparative obscurity to its present important position. In 1836 it received the grant of a market, in 1861 obtained the privilege of returning a member to parliament, in 1877 was created a municipal borough, and in 1888 a county borough. The main streets are laid out with great regularity, crossing each other at right angles, and about 20 yards wide; but the back streets are narrow and the houses mean. The park, 180 acres in extent, was laid out at a cost of 140,000; and there is another park in Tranmere, called Mersey Park, of 29 acres and 33,000 cost, opened in 1885. The principal public buildings are the market-hall, the new town-hall, the new sessions and police courts, the borough hospital, the free library, and the public baths. A railway bridge over the Mersey at Runcorn, opened for traffic in 1869, shortened by 10 miles the distance between the Liverpool and Birkenhead docks; and the Mersey railway tunnel, 1230 yards long, was opened by the Prince of Wales in 1886. There is also communication with Liverpool by ferry-steamers. The idea of constructing docks here was due to the Messrs Laird, who in 1824 purchased from the Liverpool corporation, at a very low price, a large piece of ground on the borders of the Wallasey Pool The first dock, however, was not opened till 1847. In 1857 the Birkenhead docks were amalgamated with those of Liverpool, and vested in one public trust, called 'The Mersey Docks and Harbour Board.' Including the Great Float, an immense harbour, constructed on the site of Wallasey Pool, with an area of over 140 acres, they extend from Woodside to Seacombe, a distance of about a mile, the total area being about 170 acres, with 9 1/2 miles of quayage. The corn-warehouses at Seacombe constitute a vast pile of buildings, and a great deal of coal is shipped from the port. Birkenhead is celebrated for its shipbuilding yards, some of the largest iron ships afloat having been built here. In the neighbourhood of the docks are the Canada Works for the construction of gigantic bridges, the Britannia Machinery Works, the Birkenhead Forge, etc. There are also oil-cake mills, extensive flour-mills, wagon-works, and several smaller engineering works. St Aidan's College, an Anglican theological college, is in the suburb of Claughton. Pop. (1821) 236; (1861) 54,649; (1891) 99,S57; (1901) 110,915.