THE rapid advance of the frontier settlement into the Ohio Valley following the Treaty of Fort Stanwix of 1768 was destined to encounter the resistance of the Indian tribes of the Northwest in the period from 1774 to 1795, a resistance that was made more effective during and after the Revolution by the support of the British authorities in the Great Lakes region. The military operations of the Revolutionary period in the West were a part of one cycle in the long struggle between the Indians and the frontiersmen for the possession of the interior of the continent. Nevertheless those operations played their part in the winning of independence, for they served to protect the rear of the American forces and to prevent the British and their Indian allies from attempting to sever the long thin line of the revolutionists by a thrust from the West.
The strategic situation of southwestern Pennsylvania at the head of the Ohio Valley and the fact that it had been occupied by settlers before the outbreak of the war made it the center of transmontane military operations and of Indian relations during the struggle. Fort Pitt was the headquarters of the Continental forces west of the mountains, except for a brief period when they were at Fort McIntosh at the mouth of the Beaver, and Pittsburgh was the residence of the Continental Indian agent for the middle department and the scene of numerous treaties or conferences with the Indians. The fact that the frontiersmen were able to maintain and even increase their settlements in the upper Ohio country during the war made possible the occupation of Kentucky and the operations of George Rogers Clark in the Illinois country and presumably contributed to the conviction of British statesmen at the end of the war that the western boundary of the new nation should be the Mississippi River rather than the Appalachian Mountains.