PA a state in the northeastern US, which produces large amounts of steel and coal. It was one of the 13 original US states, and was an important centre in the fight to become independent from Britain during the American Revolutionary War. officially Commonwealth of Pennsylvania State (pop., 2000: 12,281,054), middle Atlantic region, U.S. It covers 45,333 sq mi (117,412 sq km); its capital is Harrisburg. The state is bounded on the north by Lake Erie and New York; on the east by New York and New Jersey; on the south by Delaware, Maryland, and West Virginia; and on the west by the panhandle of West Virginia and by Ohio; the Delaware River forms part of the eastern boundary. The Monongahela River unites with the Allegheny River at Pittsburgh to form the Ohio River. The area was inhabited by Indian peoples, including the Shawnee and Delaware, when Europeans arrived in the 17th century. In 1664 the English seized control of the region, and in 1681 the English king granted a charter to William Penn, who established a Quaker colony based on religious tolerance in 1682. Much of the fighting of the French and Indian War took place there. The first and second Continental Congresses met in Philadelphia, and the Declaration of Independence was signed there in 1776. One of the original states of the Union, it was the second state to ratify the U.S. Constitution in 1787. During the American Civil War it was a centre of military activity (see Battle of Gettysburg). The postwar period brought great economic, industrial, and population growth, consolidating the state's position as a major commercial power. It is one of the most prosperous states, with an economy based on farming, mining, manufacturing, and high technology. The state continues to produce much of the nation's specialty steel and an abundance of coal. Philadelphia and Pittsburgh are major ports with fine educational, cultural, and musical institutions. Commonwealth of Pennsylvania Pennsylvania University of Pennsylvania Railroad Co. Pennsylvania State University