What was the main outcome of the Adams-Onis Treaty?

The primary outcome of the Adams-Onis Treaty was the loss of Spanish claims to Texas in exchange for the U.S. acquiring Florida. This treaty, signed in 1819, was significant in shaping the territorial boundaries of the United States. Under this agreement, Spain ceded Florida to the U.S. while the U.S. relinquished any claims to Texas, which was then part of Spanish territory. This effectively clarified and settled tensions regarding the borders, allowing for further westward expansion by the U.S., without Spanish interference in the region that would lead to its eventual annexation of Texas.

Other potential outcomes listed do not reflect the main provisions of the treaty. For instance, while the treaty influenced border definitions, the specific securing of the Rio Grande as a boundary was a later development during the Mexican-American War. Thus, the main focus of the Adams-Onis Treaty was indeed about the transfer of claims and territorial adjustments related to Florida and Texas.