Ohio County Chronology

Ohio, Monongalia and Yohogania was created by Virginia from West Augusta District in 1776. Ohio, Monongalia and Yohogania overlapped territory claimed by Pennsylvania in Westmoreland, Washington and Fayette County. Ohio lost to Westmoreland (PA) when Pennsylvania regained effective jurisdiction of the Pittsburgh region from Virginia in 1780. Ohio gained all of Yohogania when Yohogania was eliminated in 1785. Virginia formally terminated jurisdiction over counties in soutwestern Pennsylvania, including Fayette, Washington and Westmoreland in 1797. Ohio lost to creation of Brooke in 1797. Ohio lost to creation of Tyler in 1814. Ohio River and its islands, previously unassigned to particular counties, were declared to be part of the adjacent Virginia counties, including Ohio in 1820. In 1835, Ohio lost to creation of Marshall. Ohio separated from Virginia and became a county in the state of West Virginia in 1863.