Before the Colony of Virginia and the Province of Pennsylvania agreed to extend the Mason-Dixon line westward from the western boundary line of the Province of Maryland, both claimed a large area of what is now southwestern Pennsylvania.

The area was sparsely populated in the years following the French and Indian War (1754–63), and neither colony made any serious attempts at forming a local government until the early 1770s.

Pennsylvania later established Westmoreland County with its seat at Hannastown, overlapping Virginia's claims.

The preamble to a later act defined the boundaries of West Augusta as follows: The following several years were contentious.

In August 1776, Augusta Town became the site of the first court west of the Monongahela River.