What country claimed the lands west of the colonies in the 1900

Americans of the Revolutionary Era regarded the "West" as those lands between the Appalachian Mountains and the Mississippi River. The area beyond the Mississippi was then largely unexplored and in the possession of foreign powers. The West had been the object of much recent contention; Britain and France bitterly struggled for control of the area during the French and Indian War (1754-1763). In the aftermath of that conflict, Britain attempted to halt the westward movement of American settlers in the Proclamation of 1763, one of a series of events that led to the estrangement of mother country and colonies.