Pennsylvania officially the Commonwealth of Pennsylvania, is a state in the Mid-Atlantic and Northeastern regions of the United States. The Commonwealth is bordered by Delaware to the southeast, Maryland to the south, West Virginia to the southwest, Ohio to the west, Lake Erie and the Canadian province of Ontario to the northwest, New York to the north, and New Jersey to the east, while the Appalachian Mountains run through its middle.
The state is one of the 13 original founding states of the United States; it came into being in 1681 as a result of a royal land grant to William Penn, the son of the state's namesake. Part of Pennsylvania (along the Delaware River), together with the present State of Delaware, had earlier been organized as the Colony of New Sweden. It was the second state to ratify the United States Constitution, on December 12, 1787. Independence Hall, where the United States Declaration of Independence and United States Constitution were drafted, is located in Philadelphia, the state's largest city. During the American Civil War, the Battle of Gettysburg was fought in the south central region of the state. Valley Forge near Philadelphia was General Washington's headquarters during the bitter winter of 1777–78.
Pennsylvania is 170 miles (274 km) north to south and 283 miles (455 km) east to west. Of a total 46,055 square miles (119,282 square kilometres), 44,817 square miles (116,075 square kilometres) are land, 490 square miles (1,269 square kilometres) are inland waters, and 749 square miles (1,940 square kilometres) are waters in Lake Erie. It is the 33rd-largest state in the United States. Pennsylvania has 51 miles (82 km) of coastline along Lake Erie and 57 miles (92 km) of shoreline along the Delaware Estuary. Of the original Thirteen Colonies, Pennsylvania is the only state that does not border the Atlantic Ocean.
The boundaries of the state are the Mason–Dixon line (39°43' N) to the south, the Twelve-Mile Circle on the Pennsylvania-Delaware border, the Delaware River to the east, 80°31' W to the west and the 42° N to the north, except for a short segment on the western end, where a triangle extends north to Lake Erie.
Cities include Philadelphia, Reading, Lebanon and Lancaster in the southeast, Pittsburgh in the southwest, the tri-cities of Allentown, Bethlehem, and Easton in the central east (known as the Lehigh Valley). The northeast includes the former anthracite coal mining cities of Scranton, Wilkes-Barre, Pittston, Nanticoke, and Hazleton. Erie is located in the northwest. State College serves the central region while Williamsport serves the commonwealth's north-central region as does Chambersburg the south-central region, with York, Carlisle, and the state capital Harrisburg on the Susquehanna River in the east-central region of the Commonwealth and Altoona and Johnstown in the west-central region.
The state has five geographical regions, namely the Allegheny Plateau, Ridge and Valley, Atlantic Coastal Plain, Piedmont, and the Erie Plain.
