Chester County, Pennsylvania
Chester County, colloquially referred to as Chesco, is a county in the U.S. state of Pennsylvania. It is located in the Philadelphia metropolitan area, part of the southeastern portion of the state. As of the 2020 census, the population was 545,823, increasing by 7.1% from 498,886 during the 2010 census. The county seat is West Chester. The most populous of the county's 73 municipalities, including cities, boroughs, and townships is Tredyffrin Township. The most populous boroughs are West Chester and Phoenixville. Coatesville is the only municipality in the county that is classified as a city.
Chester County was one of the three original Pennsylvania counties created by William Penn in 1682. It was named for Chester, England. It is part of the Philadelphia-Camden-Wilmington, PA-NJ-DE-MD metropolitan statistical area. Along with northern Delaware County and southern Montgomery County, eastern Chester County is home to many communities that comprise part of the Philadelphia Main Line western suburbs of Philadelphia.
As of 2020, the county had the highest median household income level in Pennsylvania, and the 35th-highest in the nation.