Thomas Penn was an English landowner and mercer who was the chief proprietor of Pennsylvania from 1746 to 1775. He was one of 17 children of William Penn, the founder of the colonial-era Province of Pennsylvania in British America. In 1737, Thomas Penn negotiated the Walking Purchase, a contested land cession treaty he negotiated with Lenape chief Lappawinsoe that transferred control over 1,200,000 acres (4,860 km2) of territory in the present-day Lehigh Valley and Northeastern Pennsylvania regions of Pennsylvania and a portion of West Jersey in colonial New Jersey from the Lenape tribe to the Province of Pennsylvania.

The Walking Purchase, also known as the Walking Treaty, was a 1737 agreement between the family of William Penn, the original proprietor of the Province of Pennsylvania, and the Lenape native Indians. In the purchase, the Penn family and proprietors claimed that a 1686 treaty with the Lenape ceded an area of 1,200,000 acres (4,860 km2) in present-day Lehigh Valley and Northeastern Pennsylvania in colonial Pennsylvania, which included a western land boundary extending as far west as a man could walk in a day and a half, which led to its name.