The Adams-Onís Treaty was negotiated in response to Andrew Jackson’s incursion into Florida to stop the raids of the Seminole Indians on U.S. settlements along the border. Signed on February 22, 1819, and ratified by the United States in 1821, the treaty granted to the United States Florida and former Spanish territory west of the Sabine River, along a new boundary line north of Texas, New Mexico, Utah, Nevada, and California.