According to the NACo, the county seat of Chester County, Pennsylvania, is West Chester.
Chester, PA is located on the Delaware River, about 10-15 mi south of Philadelphia ... almost exactly half way between Philadelphia and Wilmington, DE
Chester county
According to the NACo, the county seat for Adams County, Pennsylvania, is Gettysburg.
Washington PA is 1 hour south of Pittsburg PA. Washington (city) is the county seat of Washington County PA.
The address of the Chester County Historical Society is: 225 N High St, West Chester, PA 19380-2658
The address of the Chester County Historic Preservation Network is: Po Box 174, West Chester, PA 19381-0174
Towamensing Township, Carbon County PA - Phone 610 681 4202
330 miles
Chester Pennsylvania is surrounded by 4 counties in PA, they are Lancaster, Berks, Montgomery, and Delaware Counties. New Castle County in DE and also Cecil County in MD.
According to fedstats.gov, the estimated population of Bucks County, Pennsylvania, is 623,205.
Erie, PA is in Erie County.
Sullivan County
It is in Tioga County.