Who/what was most responsible for the settlement of the American frontier? The Treaty of Paris the Second Continental Congress unofficial colonial groups the French Armed Forces

The Treaty of Paris was most responsible for the settlement of the American frontier, since it entailed the recognition of the United States as an independent nation and the possibility for the country to secure and eventually occupy all the land east of the Mississippi River (except for Florida and British Canada), as well as the opportunity for the settlers to finally expand and settle west of the Appalachian Mountains - they had been prevented from doing so by the British.