Soon after the glacier receded from what is now Pennsylvania, about 20,000 years ago, nomadic hunters from the west moved up the Ohio River, penetrated the passes through the Allegheny Mountains, and moved down the Susquehanna and Delaware rivers. By about AD 500, the earliest Indians, already accustomed to fishing and gathering nuts, seeds, fruit, and roots, were beginning to cultivate the soil, make pottery, and build burial mounds. Over the next thousand years, the Indians became semisedentary, or only seasonal, nomads.
Woodland Indians living in Pennsylvania, mostly of the Algonkian language family, were less inclined toward agriculture than other Indian tribes. The first Europeans to sail up the Delaware River found the Leni-Lenape ("original people"), who, as their name signified, had long occupied that valley, and whom the English later called the Delaware. Other Algonkian tribes related to the Leni-Lenape were the Nanticoke, who ranged along the Susquehanna River, and the Shawnee, who were scattered throughout central Pennsylvania. The other major Indian language group in Pennsylvania was Iroquoian. This group included the Susquehanna (Conestoga), living east of the Susquehanna River and south to the shores of Chesapeake Bay; the Wyandot, along the Allegheny River; and the Erie, south of Lake Erie. Proving that tribes related by language could be deadly enemies, the Iroquoian Confederacy of the Five Nations, located in what is now New York, destroyed the Iroquoian-speaking Erie in the 1640s and the Susquehanna by 1680. The confederacy conquered the Leni-Lenape by 1720 but failed to destroy them.
The first European to reach Pennsylvania was probably Cornelis Jacobssen, who in 1614 entered Delaware Bay for Dutch merchants interested in the fur trade. In 1638, the Swedes began planting farms along the Delaware River; they lived in peace with the Leni-Lenape and Susquehanna, with whom they traded for furs. Under Governor Johan Printz, the Swedes expanded into present-day Pennsylvania with a post at Tinicum Island (1643) and several forts along the Schuylkill River. The Dutch conquered New Sweden in 1655, but surrendered the land in 1664 to the English, led by James, Duke of York, the brother of King Charles II and the future King James II.
The English conquest was financed partly by Admiral William Penn, whose son, also named William, subsequently joined the Society of Friends (Quakers), a radical Protestant sect persecuted for espousing equality and pacifism. Dreaming of an ideal commonwealth that would be a refuge for all persecuted peoples, Penn asked Charles II, who had not paid the debt owed to Penn's father, to grant him land west of the Delaware. The Duke of York willingly gave up his claim to that land, and Charles II granted it in 1681 as a proprietary colony to the younger Penn and named it Pennsylvania in honor of Penn's father.
As proprietor of Pennsylvania, Penn was given enormous power to make laws and wars (subject to approval by the king and the freemen of Pennsylvania), levy taxes, coin money, regulate commerce, sell land, appoint officials, administer justice, and construct a government. From the beginning, Penn virtually gave up his lawmaking power and granted suffrage to property holders of 50 acres or £50. Even before coming to Pennsylvania, he forged his first Frame of Government, a document that went into effect 25 April 1682 but lasted less than a year. Under it, a 72-member council, presided over by a governor, monopolized executive, legislative, and judicial power, although a 200-member assembly could veto or amend the council's legislation. Arriving in the colony in October 1682, Penn approved the location and layout of Philadelphia, met with the Leni-Lenape to acquire land and exchange vows of peace, called for elections to select an assembly, and proposed a Great Law that ranged from prescribing weights and measures to guaranteeing fundamental liberties.
When the First Frame proved unwieldy, Penn on 2 April 1683 approved a Second Frame, which created an 18-member council and a 36-member assembly. A conspicuous friend of the deposed James II, Penn lost control of Pennsylvania from 1692 to 1694, and it was during this period that the legislature began to assert its rights. Penn returned to the colony in 1699, and on 28 October 1701 approved yet another constitution, called the Charter of Privileges. This document lodged legislative power in an annually elected unicameral assembly, executive power in a governor and council, which he now appointed, and judicial power in appointed provincial judges and an elected county judiciary. The Charter of Privileges remained in force until 1776.
As Pennsylvania's government evolved, its population grew steadily. Most of the first immigrants were from the British Isles and Germany. From 1681 to 1710, numerous English and Welsh Quaker migrants populated a 25-mi (40-km) zone surrounding Philadelphia. By 1750, most German immigrants were settled in a semicircular zone some 25–75 mi (40–120 km) from Philadelphia. A third and outermost ring, extending roughly 75 mi (120 km) west and north of the Germans, was populated beginning in 1717 by the Scots-Irish, who were indifferent farmers, but known as aggressive pioneers. By 1776, each of the major groups—which remained quite distinct—constituted roughly a third of the 300,000 Pennsylvanians. Minorities included about 10,000 Scots, 10,000 Irish Catholics, 8,000 French Huguenots, 8,000 black slaves (despite Quaker hostility to slavery), and 1,000 Jews.
A key issue during the pre-Revolutionary period was the size and extent of the colony. Conflicting colonial charters, reflecting vague English ideas of American geography, brought all of Pennsylvania's boundaries except the Delaware River into dispute. After a protracted struggle, Pennsylvania and Maryland agreed upon a basis for Charles Mason and Jeremiah Dixon to run the famous line (1763–67) that divided North and South. Although Virginia and Pennsylvania both claimed the area around Pittsburgh, a joint commission agreed in 1779 to extend the Mason-Dixon line west the full five degrees prescribed in Penn's original charter. Five years earlier, the Penn family had abandoned to New York land north of the 42nd parallel. This was confirmed as Pennsylvania's northern border in 1782, when the US Congress rejected Connecticut's claim to the Wyoming Valley area, where skirmishes (called the Yankee-Pennamite wars) had been going on since the 1760s.
Pennsylvania moved rapidly toward independence after the British victory in the French and Indian War. The Proclamation of 1763, preventing settlement west of the Alleghenies, outraged western Pennsylvania, while the Stamp Act (1765), Townshend Acts (1767), and Tea Act (1773) incensed Philadelphians. Although the Continental Congress began meeting in Philadelphia in September 1774, Pennsylvania revolted reluctantly. In July 1776, only three Pennsylvania delegates to the Second Continental Congress voted for independence, while two were opposed and two absented themselves from the vote. Nevertheless, the Declaration of Independence was proclaimed from Independence Hall, Pennsylvania's State House, on 4 July 1776. As the headquarters of the Congress, Philadelphia was an important British target. The American defeat at the Battle of Brandywine Creek on 11 September 1777 led to the British occupation of the city. The provisional capital was moved first to Lancaster and then to York, where the Articles of Confederation were drafted. Following battles at Germantown and Whitemarsh, General George Washington set up winter headquarters at Valley Forge, remaining there from December 1777 to June 1778. Faced with the threat of French naval power intervening on behalf of the Americans, the British evacuated Philadelphia during the spring of 1778, and Congress reconvened there on 2 July. Philadelphia would serve as the US capital until 1783, and again from 1790 to 1800.
With independence, Pennsylvania adopted the state constitution of 1776, which established a powerful unicameral assembly elected annually by all freemen supporting the Revolution, a weak administrative supreme executive council (with a figurehead president), an appointed judiciary, and a council of censors meeting every seven years in order to take a census, reapportion the assembly, and review the constitutionality of state actions. In 1780, Pennsylvania passed the first state law abolishing slavery. Seven years later, Pennsylvania became the second state to ratify the US Constitution and join the Union. In 1790, Pennsylvania adopted a new constitution, modeled on the federal one, allowing all taxpaying males to vote. This document provided for a powerful governor, elected for a three-year term and eligible to succeed himself twice, a bicameral legislature (with senators elected every four years and a house elected annually), and an appointed judiciary.
Opposition to national taxes was evidenced by two disturbances in the 1790s. In 1794, western Pennsylvania settlers, opposed to a federal excise tax on distilled spirits, waged the Whiskey Rebellion. The insurrection was soon quashed by state troops under federal command. The levying of a federal property tax inspired the unsuccessful Fries Rebellion (1799) among Pennsylvania Germans.
By 1800, the first stages of industrialization were at hand. Pittsburgh's first iron furnace was built in 1792, and the increasing use of coal as fuel made its mining commercially feasible. The completion of the Main Line of Public Works, a canal and rail system connecting Philadelphia with Pittsburgh, was a major development of the early 19th century, which was otherwise a period of political turmoil and shifting party alliances.
By 1838, Pennsylvania adopted a new constitution curtailing the governor's power (he could serve only two three-year terms in a nine-year period), making many judgeships elective for specific terms, restricting the charter of banks, and disenfranchising black people. The 1840s saw not only an influx of Irish immigrants but also the rise of the Native American (Know-Nothing) Party, an anti-Catholic movement. The antislavery crusade, which gave birth to the Republican Party, influenced state politics during the following decade.
Although a Pennsylvania Democrat, James Buchanan, carried the state and won the presidency in 1856, the Republicans captured Pennsylvania for Abraham Lincoln in 1860, partly by their strong support for a protective tariff. Protectionism attracted Pennsylvania because, in addition to its enormously productive farms, it was heavily industrialized, leading the nation in the production of iron, lumber, textiles, and leather.
Pennsylvania rallied to the Union cause, supplying some 338,000 men, a figure exceeded only by New York. The state was the scene of the Battle of Gettysburg (1–3 July 1863), a turning point in the war for the Union cause. Under General George Gordon Meade, the Union troops (one-third of whom were Pennsylvanians) defeated Confederate forces under General Robert E. Lee, who was then forced to lead a retreat to Virginia.
The Civil War left the Republican Party dominant in Pennsylvania, but, in the postwar years, the Republicans were themselves dominated by industry, particularly the Pennsylvania Railroad. Between 1890 and 1900, the state was the nation's chief producer of coal, iron, and steel, and for much of that period the main source of petroleum and lumber. Farmers' sons and daughters joined immigrants from abroad in flocking to the anthracite and bituminous coal regions and to Philadelphia, Pittsburgh, and other urban centers to work in mines, mills, and factories. As the state's industrial wealth increased, education, journalism, literature, art, and architecture flourished in Philadelphia and Pittsburgh. The 1876 Centennial Exhibition at Philadelphia illustrated America's advancement in the arts and industry.
Pennsylvania adopted a reform constitution in 1873, increasing the size of the senate and house to reduce the threat of bribery, prescribing rules to prevent treachery in legislation and fraud at the polls, equalizing taxation, limiting state indebtedness, restricting the governor to one four-year term in eight years, and creating the office of lieutenant governor. None of this, however, seriously hampered the Republican political machine, led by Simon Cameron, Matthew Quay, and Boies Penrose, which dominated the state from the 1860s to the 1920s. Though Progressive reforms were enacted in subsequent years, the Penrose machine grew ever more efficient, while industrial leaders—supported both by the Pennsylvania state government and by society at large—smashed labor's efforts to unite, particularly in the great steel strike of 1919.
During the nationwide boom years of the 1920s, Pennsylvania did little more than hold its own economically, and its industrial growth rate was low. The state's share of the nation's iron and steel output no longer exceeded that of the rest of the country combined. Coal, textiles, and agriculture—all basic to the state's economy—were depressed. When Penrose died in 1921, at least five factions sought to control the powerful Pennsylvania Republican Party. In this confusion, Gifford Pinchot, a Progressive disciple of Theodore Roosevelt, won the governorship for 1923–27 and reorganized the state's administration, but failed in his attempt to enforce prohibition and to regulate power utilities.
The disastrous depression of the 1930s brought major changes to Pennsylvania. Serving again as governor (1931–35), Pinchot fought for state and federal relief for the unemployed. The Republican organization's lack of enthusiasm for Pinchot and Progressivism helped revive the state Democratic Party long enough to secure the election in 1934—for the first time since 1890—of its gubernatorial nominee, George H. Earle. As governor, Earle successfully introduced a Little New Deal, supporting labor, regulating utilities, aiding farmers, and building public works. With government support, coal miners, steelworkers, and other organized labor groups emerged from the Depression strong enough to challenge industry. Full employment and prosperity returned to Pennsylvania with the unprecedented demands on it for steel, ships, munitions, and uniforms during World War II.
Despite their professed opposition to government control, the Republican administrations (1939–55) that succeeded the Earle regime espoused and even enlarged Earle's program. They regulated industry, improved education, and augmented social services, at the same time increasing state bureaucracy, budgets, and taxes. Markets, transportation, banks, factories, machinery, and skilled labor remained abundant. Two Democratic governors were able to attract new industries to the state during the 1950s and early 1960s. However, the economy was still not healthy in 1963, when Republican William W. Scranton entered the statehouse (1963–67). Scranton continued both to enlarge state responsibilities (through increased taxes) and to secure federal aid for economic and social programs. He was rewarded with four years of steady economic growth. Pennsylvania's unemployment level, 2nd highest in the nation from 1950 to 1962, had dropped below the national average by 1966. The 1873 constitution was extensively revised at a constitutional convention held in 1967–68, during the administration of Raymond P. Shafer (1967–71), Scranton's Republican successor.
Pennsylvania faced an unresolved financial crisis in 1971 when Democrat Milton J. Shapp became governor. During his first term (1971–75), Shapp weathered the storm by securing passage of a state income tax. He virtually eliminated state patronage by signing union contracts covering state employees. Not only did he continue to attract business to Pennsylvania, but he also championed the consumer with no-fault auto insurance, adopted in 1974. Shapp's second term, however, was wrecked by his pursuit of the 1976 presidential nomination and by rampant corruption among Pennsylvania Democrats. Shapp's successor, Republican Richard L. Thornburgh, had scarcely been seated in the governor's chair before the release of radioactive gases resulting from the malfunction of one of the two nuclear reactors at Three Mile Island in March 1979 confronted him—and others—with vexing questions concerning the safety and wisdom of atomic power. Nevertheless, in September 1985, during Thornburgh's second term, and following six years of cleanup of radioactive waste, the undamaged reactor at Three Mile Island was restarted.
In the mid-1980s, Pennsylvania found itself confronted with the problem of completing the transition from a manufacturing to a service economy. While some parts of the state, namely southeastern Pennsylvania and Philadelphia, had successfully negotiated the transition, the economies of Pittsburgh, Lehigh Valley, Scranton, and Wilkes-Barre remained centered on the depressed steel and coal industries. Under Governor Robert Casey, who took office in 1987, Pennsylvania created an organization called the Governor's Response Team to assist ailing industries in the state. The team helped companies obtain low-interest loans and subsidized companies that sought to retrain their workers. In the first year of its existence, the team reached out to assist 214 companies, saved 10,000 existing jobs, and created 10,000 new ones.
In the mid-1990s, steel was no longer the mainstay of industry in Pennsylvania, although the state still led the nation in production of specialty steel. Important manufacturing sectors included food processing and chemicals, especially pharmaceuticals. Philadelphia had become a center for high-technology industries, while Pittsburgh was a mecca for corporate headquarters. By 2000 the state's economy was described as "relentlessly strong" by one newspaper, and legislators considered $643.5 million in tax cuts to residents and businesses along with increased spending in education and health care. As in many other regions of the nation, one of the byproducts of Pennsylvania's robust economy was urban sprawl. A landmark in the anti-sprawl movement, in June 2000 Republican Governor Tom Ridge signed into law a plan that encouraged local governments to work together, allowed them to determine growth areas, and required state agencies to comply with community development guidelines.
In 1996 Governor Ridge approved the deregulation of the state's electrical utilities. Four years later, a report indicated the move had helped the economy (by lower consumer bills) but would result in lower tax revenues (due to restructuring and lower prices). While computer models forecasted that by 2004 reductions in electric rates under deregulation would lead to $1.9 billion in additional economic output, a $1.4-billion increase in personal income, and 36,000 new jobs, legislators had not yet addressed the projected shortfall in tax revenues, which would affect public transportation and municipalities.
The state remained one of the nation's most populous, ranking 5th both in the 1990 census and 1995 estimates, before slipping to 6th (with over 12.2 million people) in 2000.
Following the 11 September 2001 terrorist attacks on the United States, President George Bush proposed the creation of a cabinet-level Department of Homeland Security. Former Governor Tom Ridge was named first secretary of the department.
Democratic Governor Ed Rendell, elected in 2002, was the first former Philadelphia mayor to become Pennsylvania governor in 90 years. Rendell pledged to lower property taxes by one-third during his first year in office, raise income taxes, and to provide prescription drug coverage for senior citizens. He favored the introduction of slot machines at the state's racetracks and increasing school spending. In 2003, Pennsylvania faced a $2.4 billion budget deficit for fiscal year 2003/04.