About Chester County, PA

Chester County (Pennsylvania Dutch: Tscheschter Kaundi), colloquially known as Chesco, is a county in the southeastern part of the U.S. state of Pennsylvania. As of the 2020 census, the population was 534,413, increasing by 7.1% from 498,886 in 2010. The county seat and most populated municipality is West Chester. Chester County was one of the three original Pennsylvania counties created by William Penn in 1682. It was named for Chester, England. Chester County is part of the Philadelphia-Camden-Wilmington, PA-NJ-DE-MD Metropolitan Statistical Area. Eastern Chester County is home to many communities that comprise part of the Philadelphia Main Line western suburbs outside of Philadelphia, while part of its southernmost portion is considered suburban Wilmington, along with southwest Delaware County. == History == Philadelphia, Bucks, and Chester were the three Pennsylvania counties initially created by William Penn on August 24, 1682. At that time, Chester County's borders were Philadelphia County to the north, the ill-defined western edge of the colony (approximately the Susquehanna River) to the west, the Delaware River to the east, and Delaware and Maryland to the south. Chester County replaced the Pennsylvania portion of New Netherland/New York’s "Upland", which was officially eliminated when Pennsylvania was chartered on March 4, 1681, but did not cease to exist until June of that year.