Pennsylvania

State in northeastern USA bordered to the north by New York, with a coastal strip on Lake Erie, to the west by Ohio and the West Virginia panhandle, to the south, on the Mason–Dixon Line, by West Virginia, Maryland, and Delaware, and to the east by New Jersey, across the Delaware River; area 116,075 sq km/44,817 sq mi; population (2006) 12,440,600; capital Harrisburg. It is nicknamed the Keystone State due to its geographical position between the northeast and south of the USA. The Appalachian Plateau dominates over half of Pennsylvania, defined on its eastern border by the Allegheny Front, a spine of mountains running diagonally southwest–northeast across the centre of the state. The Susquehanna and the Juniata rivers cut east–southeast across the front. One of the original Thirteen Colonies, Pennsylvania is a leader in both agriculture and industry, producing hay, cereals, dairy products, coal, steel, petroleum products, and textiles. Philadelphia is the state's most populous city; other major cities include Pittsburgh, Erie, Allentown, Reading, and Scranton. Pennsylvania was home to several Iroquoian and Algonquian tribes, including the Delaware, Shawnee, Susquehannock, and Seneca. First explored by the English and the Dutch, and fought over by early Swedish and Dutch settlers, Pennsylvania became an English colony in 1681. Pennsylvania played a key role in the American Revolution and in the founding of the new American government: the Declaration of Independence, the Articles of Confederation, and the US Constitution were written in Philadelphia. The state became the second to join the Union, in 1787.