The earliest known signs of human activity in Pennsylvania date back over 10,000 years at the Meadowcroft Rockshelter. This site predates the Clovis culture and suggests people crossed into North America between 10,000 and 16,000 years ago during the Last Glacial Period.
King Charles II granted William Penn a land charter for the Province of Pennsylvania in 1681. Penn was a Quaker who sought religious tolerance and established peaceful relations with native tribes through treaties like the Treaty of Shackamaxon signed with Tamanend leader of the Lenape.
The Battle of Gettysburg took place from July 1 to 3 1863 near the town of Gettysburg resulting in over 51,000 Union and Confederate casualties making it the bloodiest battle in American history. The Union victory proved to be the turning point of the war leading to ultimate success two years later.
Western Pennsylvania birthed the U.S. oil industry while coal mining became a major industry throughout much of the nineteenth and twentieth centuries primarily in the state's Coal Region. Andrew Carnegie founded the Carnegie Steel Company in Pittsburgh and Milton S. Hershey began construction on a chocolate factory in Hershey in 1903 that grew into North America's largest chocolate manufacturer.
The 2020 U.S. census counted 13,011,844 residents making Pennsylvania the fifth-most populous state after California Texas Florida and New York. As of 2024 Pennsylvania has an Amish population of 92,660 representing the largest number in any state.
On the 12th of December 1787 Pennsylvania became the second state to ratify the U.S. Constitution after Delaware. The Constitution was drafted and signed at the Pennsylvania State House in Philadelphia now known as Independence Hall.