Chester County was named for Chester, Pennsylvania by early Scots-Irish settlers who arrived in the area as early as 1755. Many belonged to the Fishing Creek Presbyterian Church. Early Scots-Irish settlers immigrated south from Pennsylvania on the Great Wagon Road. Others came up from the port of Charleston. The western part of the county was settled for the most part by immigrants from Virginia, most of English extraction. Source: http://www.villageprofile.com/southcarolina/chestercounty/chester1.html
York County to the north, Lancaster County on the east, Fairfield County to the south and Union County in the west.