There are 4 US Post Offices in Lancaster County serving a total of 61,736 residents equating to 15,434 residents per post office. It's estimated that approximately 98,538 packages are handled across the 4 county post offices annually. Lancaster County /\u02c8le\u026a\u014bk\u0259st\u0259r/ is a county located in the U.S. state of South Carolina. As of the 2015 census estimate, its population was 85,842. Its county seat is Lancaster which has an urban population of 23,979. The county was created in 1785. Lancaster County is included in the Charlotte-Concord-Gastonia, NC-SC Metropolitan Statistical Area. It is located in the Piedmont region."