Upper Darby Township (often shortened to simply Upper Darby) is a home rule township bordering West Philadelphia in Delaware County, Pennsylvania, United States.
In 1650, the area that eventually became Upper Darby had been inhabited by the Lenape tribe of Native Americans for hundreds of years, but war with the Susquehannock to the west along with devastating smallpox and measles epidemics had significantly reduced their numbers. The first permanent Europeans settlers arrived in late 1653 with a group from New Sweden. Soon after, in 1655, New Sweden was taken over by the Dutch, and then came under English rule in October 1664 as part England's overall conquest of New Amsterdam. The region was controlled as a possession of the English king until it was included in a large land grant to William Penn in 1681.