Secretary of State, John Quincy Adams, and Spanish minister, Luis de Onís, signed the Adams-Onís Treaty, also known as the Transcontinental Treaty, on this date in 1819, ceding the Floridas to the United States. After the end of the American Revolution, Spain received the Florida colonies back from Britain and almost immediately, tensions along the border with the newly independent United States of America began. Spain’s control of the Florida colony was severely weak and unsanctioned American raids into Spanish Florida became more frequent. The most notable of these was General Andrew Jackson’s invasion of West Florida and occupation of the city of Pensacola in 1817-1818. Although the main focus of the treaty was to secure Florida, it was also to set a western boundary between the United States and New Spain. The treaty was negotiated and signed in Washington in 1819; however, full ratification on both sides did not occur until two years later, with the official proclamation of the treaty on February 22, 1821.
~Florida Historical Society
