What was the primary outcome of the Adams-Onis Treaty of 1819?

The primary outcome of the Adams-Onis Treaty of 1819 was that the U.S. gained territory from Spain. This treaty, also known as the Transcontinental Treaty, resulted in Spain ceding Florida to the United States, thus solidifying U.S. claims over that territory. The agreement provided for the delineation of boundaries between Spanish territories and the United States, and it resolved territorial disputes stemming from the earlier Louisiana Purchase.

The U.S. did not agree to give up its claims to Texas; rather, it negotiated with Spain to clarify and solidify its territorial boundaries, which included recognizing existing claims while ceding other territories in a balanced manner. By gaining Florida and defining borders more clearly, the treaty set the stage for future expansion of the U.S. into territories that would include areas of Mexico, but it did not finalize the borders between the U.S. and Mexico as that would happen later.