What did the Adams-Onis Treaty accomplish?

The Adams-Onís Treaty, also known as the Transcontinental Treaty, was a significant agreement between the United States and Spain, signed in 1819 and ratified in 1821. This treaty was pivotal because it ceded Florida to the United States, effectively ending Spanish control in that region. Furthermore, it delineated the boundary between the U.S. and Spanish territories, specifically defining the southwestern borders of the United States.

The acquisition of Florida was important for the U.S. at the time, as it helped to eliminate a point of conflict with Spain and addressed issues related to border security and control over the southeastern parts of North America. It also facilitated U.S. expansion westward, as the defined borders allowed for a clearer understanding of territory and governance.

Understanding this treaty's implications provides insight into early U.S. foreign policy and its directional movement toward expansion during the 19th century, making the correct answer clear in the context of American territorial growth.