The western border divided colonial Pennsylvania and Indian Country along Tiadaghton Creek.
The Pennsylvanian government recognized tribal claims and so all land west of Lycoming Creek was considered Native American and off bounds for settlement until a resolution could be found.
The land was formally associated with Northumberland County, but a group of organized squatters near modern Jersey Shore elected three commissioners each March who became responsible for seeing that everyone in the area was dealt with fairly.
The following counties have been formed from land that was once part of Lycoming County: Armstrong, Bradford, Centre, Clearfield, Clinton, Indiana, Jefferson, McKean, Potter, Sullivan, Tioga, Venango, Warren, Forest, Elk and Cameron.
[4] By the beginning of the 20th century, the extensive harvesting led to deforestation and subsequent decline of lumber industry in the region.