France and Spain had not defined a boundary between Louisiana and neighboring territory retained by Spain, leaving this problem for the U.S. and Spain to sort out. The U.S. inherited the French claims to Texas, then in the 1819 Adams–Onís Treaty traded these (and a little of the Mississippi drainage itself) in return for American possession of Florida, where American settlers and the U.S. Army were already encroaching, and acquisition of Spain's weak claims to the Pacific Northwest. Before three more decades had passed, the United States had annexed Texas.