Deciding which state had the rights to southwestern Pennsylvania was a contentious affair that lasted from the end of the French & Indian war to the beginning of the new republic. Once the French left, Virginians began to move into the area. It was much easier for settlers to come up from Virginia via Braddock's Road (Route 40)rather than over the Allegheny Mountains from the eastern part of Pennsylvania. The Pennsylvanians who came were interested in trading with the Indians; the Virginians in taking their place. The British government, not wanting to spend any more money on security for the area, declared it Indian territory, effectively annoying both Pennsylvanians and Virginians and giving them yet another reason to unite against the British. After the Revolutionary War, it was up to the new government to settle the dispute. The Mason-Dixon Line, which had earlier determined the border between Pennsylvania and William Penn's claim and Maryland and Lord Calvert's claim, was extended to Pennsylvania's western border, giving the territory to Pennsylvania. By 1788, there were enough settlers around the Pittsburgh area to warrant the establishment of a new county and Allegheny County was formed out of Washington and Westmoreland Counties.