美国东部一州，属中大西洋地区。德拉瓦河为其东部州界。阿利根尼河和莫农加希拉河在匹兹堡汇合成俄亥俄河。在17世纪欧洲人抵此时，原由印第安人占据，包括肖尼人和德拉瓦人。1664年英国人夺取此区，1681年英王把这一地区授予彭威廉，他在1682年以宗教宽容的基础建立了一块贵格会殖民地。法国印第安人战争的大部分战斗是在该州进行的。第一次和第二次大陆会议是在费城召开，1776年在那里签署了「独立宣言」。是最初十三州之一，1787年加入联邦，成为美国第二个州。南北战争期间是军事活动中心（参阅Gettysburg, Battle of）。战後出现了经济、工业和人口的大幅成长，巩固了该州的强大商业势力。为经济最繁荣的一个州，以农业、矿业、制造业和高科技产业为主。该州并继续生产全国特有的钢，煤的储量亦丰。费城和匹兹堡是重要港口，拥有优良的教育、文化和音乐机构。面积117,348平方公里。首府哈利斯堡。人口约12,281,054（2000）。
State (pop., 1997 est.: 12,020,000), U.S., middle Atlantic region. It covers 45,333 sq mi (117,412 sq km); its capital is Harrisburg. The Delaware River forms part of its 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 center 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.