Chester County, Pennsylvania
Chester was an original county of Pennsylvania, one of the largest until Dauphin, Lancaster and Delaware counties were split off. Because the boundaries mainly did not follow rivers or other natural dividers, translating verbal boundaries into actual lines was highly contentious.
This topic is relatively complete, except for a gaping hole for the Battle of Brandywine, which ought to be placed in The British Attack Philadelphia, as well. Ardrossan is just a place-holder.