Adams‐Onís Treaty

Adams‐Onís Treaty (1819)This agreement, also called the Transcontinental Treaty, was made during the administration of President James Monroe and settled long‐standing disputes between the United States and Spain. Madrid ceded East Florida to the Americans, while Washington surrendered its claims to Texas and agreed to assume payment of American financial claims against the Spanish up to $5 million. The treaty established definitive western boundaries for the Louisiana Purchase, following the Sabine, Red, and Arkansas Rivers to the 42nd parallel, and running along that line to the Pacific. The United States also secured Spanish claims to Oregon.

Historians have variously interpreted the treaty's significance. Samuel F. Bemis stressed the establishment of the first American claims to territory bordering the Pacific. More recently, William E. Weeks emphasized that the treaty consummated the first phase of the United States's aggressive, nineteenth‐century territorial expansion. Strategically speaking, the Florida cession closed a vulnerable point in American coastal defenses. European powers welcomed the treaty because it ended the possibility of war between the United States and Spain. Some westerners protested the loss of Texas, but otherwise, there was little domestic opposition. The agreement was named for its principal negotiators—Secretary of State John Quincy Adams and Spain's minister to the United States, Don Luis de Onís.
[See also Expansionism.]

Bibliography

Charles C. Griffin , The United States and the Disruption of the Spanish Empire, 1810–1822, 1937.
Philip C. Brooks , Diplomacy and the Borderlands: The Adams‐Onís Treaty of 1819, 1939.
Samuel Flagg Bemis , John Quincy Adams and the Foundations of American Foreign Policy, 1949.
William E. Weeks , John Quincy Adams and American Global Empire, 1992.

Michael S. Fitzgerald