1819 - Secretary Of State John Quincy Adams and Spanish minister Luis de Onís signed the Adams-Onís Treaty, also known as the Transcontinental Treaty, ceding the Floridas to the United States on this date. After the American Revolution, Spain received the Florida colonies back from Britain and almost immediately, tension along the border with the newly independent United States of America began. Spain’s colonies in Florida were severely weakened and unsanctioned American raids into Spanish Florida became more frequent, most notably General Andrew Jackson’s invasion of West Florida and occupation of Pensacola in 1817-1818. Although the focus of the treaty was to secure Florida, it also 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^nd, 1821.