Chester is a city in Delaware County, Pennsylvania within the Philadelphia Metropolitan Area. It is the only city in Delaware County and had a population of 32,605 as of the 2020 census. Incorporated in 1682, Chester is the oldest city in Pennsylvania and is located on the western bank of the Delaware River between the cities of Philadelphia and Wilmington, Delaware. It was the location of William Penn's first arrival in the Province of Pennsylvania and the county seat for Chester County from 1682 to 1788 and Delaware County from 1789 to 1851.