Pennsylvania
Pennsylvania is a historically pivotal U.S. state with diverse geography.
Pennsylvania, formally called the Commonwealth of Pennsylvania, sits at the intersection of the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It shares borders with Delaware to the southeast, Maryland to the south (along the Mason–Dixon line), West Virginia to the southwest, Ohio to the west, the Canadian province of Ontario to the northwest across Lake Erie, New York to the north, and New Jersey and the Delaware River to the east. Philadelphia is the state’s most populous city, while Harrisburg serves as the capital. As of the 2020 census, Pennsylvania ranks fifth in the nation for population, with over 13 million residents. It holds the ninth-highest population density and is the 33rd-largest state by land area. The Philadelphia metropolitan area, centered on the sixth-largest U.S. city, is the largest metro region in the state; the second-largest is Greater Pittsburgh, built around Pittsburgh, the commonwealth’s second-largest city.
The state’s geography is notably varied. The Appalachian Mountains cut through its center, while the Allegheny and Pocono mountains cover much of the northeast. Nearly 60% of Pennsylvania is forested. Although it lacks a direct ocean coastline, the state has 140 miles (225 km) of waterfront along Lake Erie and the tidal Delaware River, which flows into the Delaware Bay, a marginal bay of the Atlantic Ocean.
Pennsylvania was established in 1681 via a royal land grant to William Penn, after whom the commonwealth is named. Before that, from 1638 to 1655, a southeastern portion of the state belonged to the Swedish colony of New Sweden. Founded as a refuge for religious and political tolerance, the British colonial Province of Pennsylvania was noted for its peaceful interactions with Native tribes, an innovative government, and religious pluralism. The state played a crucial role in the American Revolution and the fight for independence from Britain. Philadelphia hosted both the First and Second Continental Congresses; the latter formed the Continental Army under George Washington in 1775 and unanimously adopted the Declaration of Independence the following year. On December 12, 1787, Pennsylvania became the second state to ratify the U.S. Constitution, just after Delaware.
In the 21st century, Pennsylvania has earned the nickname “Cellicon State” due to the key roles of Philadelphia and Pittsburgh in advancing technology and immunotherapies for various cancers. STEM education is considered a high priority for the state’s long-term goals and future.
**History**
**Indigenous settlement** Human habitation in Pennsylvania stretches back thousands of years before the colonial province was founded in 1681. Archaeologists think the first settlement of the Americas occurred at least 15,000 years ago during the Last Glacial Period, though it is uncertain when people first arrived in what is now Pennsylvania. Between 10,000 and 16,000 years ago, Native Americans crossed into North America. Meadowcroft Rockshelter in Jefferson Township contains the earliest known signs of human activity in Pennsylvania—and possibly all of North America—including remains of a civilization over 10,000 years old that may predate the Clovis culture. By 1000 AD, the native population had shifted from nomadic hunting and gathering to agriculture and a mixed food economy.
When European colonization began, at least two major Native American tribes lived in Pennsylvania. The Lenape, who spoke an Algonquian language, occupied the eastern part of the state, an area then called Lenapehoking that included most of present-day New Jersey and the Lehigh Valley and Delaware Valley regions. Their territory ended somewhere between the Delaware River and the Susquehanna River in central Pennsylvania. The Susquehannock, who spoke an Iroquoian language, lived in eastern Pennsylvania along the Susquehanna River. European diseases and constant warfare with neighboring tribes and European groups weakened both tribes, and they were financially outpaced as the Hurons and Iroquois blocked their westward movement into Ohio during the Beaver Wars. As their numbers and land shrank, the Hurons abandoned much of their western territory and moved closer to the Susquehanna River, while the Iroquois and Mohawk tribes moved farther north. The Iroquoian Petun people lived northwest of the Allegheny River.
**17th century** During the 1600s, both the Dutch and the English claimed the land on either side of the Delaware River as part of their American colonies. The Dutch were the first to take possession. On June 3, 1631, they began settling the Delmarva Peninsula by founding the Zwaanendael Colony at the site of present-day Lewes, Delaware. In 1638, Sweden established the New Sweden Colony around Fort Christina, where Wilmington, Delaware, now stands. New Sweden claimed and largely controlled the lower Delaware River region, including parts of present-day Delaware, New Jersey, and Pennsylvania, though it settled few colonists there. On March 12, 1664, King Charles II of England granted James, Duke of York a tract that included all lands from the original Virginia Company of Plymouth Grant and more. This grant conflicted with the Dutch claim to New Netherland, which included parts of today’s Pennsylvania. On June 24, 1664, the Duke of York sold the portion of his grant that contained present-day New Jersey to John Berkeley and George Carteret.
- Capital
- Harrisburg
- Largest City
- Philadelphia
- Population (2020)
- over 13 million
- Land Area Rank
- 33rd-largest
- Population Density Rank
- 9th-highest
Lore & Background
Pennsylvania’s human history reaches back many millennia before the colonial era. The earliest known evidence of habitation in the state, and possibly all of North America, comes from Meadowcroft Rockshelter, where signs of a civilization existed over ten thousand years ago, potentially predating the Clovis culture. By around 1000 AD, the native population had shifted from nomadic hunting and gathering to a mixed economy that included agriculture. When European colonization began, the Lenape, speaking an Algonquian language, occupied the eastern part of the state, while the Susquehannock, an Iroquoian-speaking people, were based along the Susquehanna River. Both tribes suffered severe population loss from European diseases and constant warfare with neighboring groups, including the Hurons and Iroquois, which also blocked their westward movement. The Hurons eventually abandoned much of their western territory and moved closer to the Susquehanna, while the Iroquois and Mohawk pushed northward. The Petun, an Iroquoian group, lived northwest of the Allegheny River.
Reader's Guide
Pennsylvania's significance stems from its central role in the founding of the United States and its industrial might. It hosted the Continental Congress, which formed the Continental Army and adopted the Declaration of Independence. In the late 19th and 20th centuries, its steel production and manufacturing built much of the nation's early infrastructure and military hardware. In the 21st century, it has been called the 'Cellicon State' for its role in developing immunotherapies for cancer. Its geography is highly diverse, with the Appalachian Mountains, extensive forests, and waterfront along Lake Erie and the Delaware River.
Did You Know?
- Pennsylvania was named by King Charles II to honor Admiral William Penn, not at the proposal of William Penn himself.
Industrial Roots and Economic Rebirth
Pennsylvania's industrial story is perhaps best told through the Lehigh Valley, a region in the eastern part of the state named after the river that threads through its landscape. In the nineteenth and twentieth centuries, Allentown—the valley's largest city and the state's third-most populous—served as a vital engine of the nation's heavy manufacturing output. Bethlehem and Easton, the region's other major urban centers, shared in that productive era, surrounded by sprawling suburban communities. Yet the late twentieth century brought a painful reckoning: the heavy manufacturing base that had defined the area for generations eroded, and the local economy contracted sharply. The early twenty-first century, however, marked a turning point. The valley's economy broadened into new sectors, and the region has since become one of the fastest-growing metropolitan areas in the state. A parallel industrial legacy persists in the Coal Region of the central Appalachians, where the largest known anthracite coal deposits on Earth—estimated at roughly seven billion tons—shaped entire communities of mining cities, boroughs, and villages across six counties.
Population Scale and Urban Hierarchy
As the fifth-most populous state in the union, Pennsylvania houses a staggering concentration of people across its varied regions. The Delaware Valley, anchored by Philadelphia—the state's largest city and the sixth-largest in the entire country—stands as the most populous region by a wide margin. Named for the river that bisects it, the valley spans five counties and held a 2020 population of roughly 6.245 million. Far to the east, the Lehigh Valley, with its 2020 count of about 687,500 across Lehigh and Northampton counties, ranks as the state's third-largest metropolitan statistical area, trailing only the Philadelphia metro and Greater Pittsburgh. The Pittsburgh region itself stretches across seven counties in the southwest, forming a distinct urban and suburban corridor. Together, these three anchors—Philadelphia, the Lehigh Valley, and Greater Pittsburgh—establish a clear hierarchy of population density that contrasts sharply with the more sparsely settled agricultural and mountainous counties scattered throughout the rest of the state.
Mountainous Terrain and Natural Wonders
Northeastern Pennsylvania is defined by its rugged topography, a landscape that includes the Pocono Mountains, the Endless Mountains, and the remnants of former anthracite coal mining communities. The Poconos, covering approximately 2,400 square miles roughly thirty miles north of Allentown, have become a nationally recognized recreational destination. In winter, visitors flock for skiing and snowboarding; in warmer months, the same terrain supports hiking, kayaking, and tubing. Geologically, the Endless Mountains present an interesting nuance: despite their name, they are not true mountains but rather a dissected plateau that forms part of the Allegheny Plateau, sharing that classification with the higher Catskill Mountains across the state line in New York. The Susquehanna River, at approximately 410 miles, is the longest waterway on the East Coast, threading through the central part of the state. To the northwest, the Allegheny National Forest blankets over 500,000 acres of land, while the Laurel Highlands in the southwest trace the Laurel and Chestnut ridges of the Allegheny Mountains. In central Pennsylvania, Happy Valley cradles the campus of Pennsylvania State University.
Cultural and Agricultural Heartland
A distinctive cultural identity runs through the central and southeastern parts of Pennsylvania. Pennsylvania Dutch Country, spanning eight counties including Lancaster, York, Berks, and Franklin, is home to a notably high concentration of Amish, Mennonite, and so-called Fancy Dutch residents. The Pennsylvania Dutch language, once widely spoken across the region, continues to be used today by many Amish communities in the state, preserving a linguistic heritage that stretches back centuries. Just to the north, the Pennsylvania Piedmont occupies a heavily agricultural section of the Piedmont Plateau, encompassing seven counties such as Dauphin, Cumberland, and Lebanon. The Cumberland Valley, nestled between South Mountain and the Blue Ridge Mountains, adds another layer to this agrarian landscape, stretching into western Maryland. South Central Pennsylvania, a broader grouping that can include as many as a dozen or more counties, further underscores how deeply farming and rural life are woven into the state's identity, standing in deliberate contrast to the urban corridors of the Delaware Valley and the industrial memory of the Lehigh Valley.
Gallery
Frequently Asked Questions
What role did Pennsylvania play in the founding of the United States?
Philadelphia, its largest city, hosted both the First and Second Continental Congresses, making the state the nerve center of the Revolutionary movement. Pennsylvania also became the second state to formally approve the U.S. Constitution, locking in its place among the nation's founding members.
Why is Pennsylvania considered so important?
Its original charter set a precedent for religious and political tolerance that shaped American values, and its central involvement in the Revolution and constitutional ratification gave it a foundational role in the republic's creation. Geographically, it stretches across multiple major regions, giving it a remarkably varied landscape.
Where does Pennsylvania stand today?
It remains a densely populated, politically active state in the northeastern United States, still functioning as a major cultural and governmental hub. Its founding legacy of tolerance and its outsized contribution to the nation's birth continue to define its identity in the broader American story.
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