 In Colonial times, and for about 100 years thereafter, Duke of Gloucester Street actually formed a prominent portion of the James City County border with York County, dividing the city down its primary street.Although Williamsburg was established literally along the border of the two counties, the unincorporated community of Yorktown along the riverfront area at the York River has always been the county seat of York County.In 1870, the Virginia General Assembly moved the county line so that Williamsburg was located entirely within James City County.