Maritime history of Florida
Spain ceded Florida to the United States as part of the Adams–Onís Treaty of 1819, and Florida became a U.S. territory in 1821. Coastal trade with other markets continued to expand and towns like Jacksonville, Pensacola and Tampa became important ports. After becoming a U.S. territory, the federal government began building a series of lighthouses as aids to navigation along the coasts of Florida to mark dangerous headlands, shoals, bars and reefs.
West Florida Controversy
The second dispute arose following the Louisiana Purchase in 1803. The controversy led to the secession of part of West Florida, known as the "Republic of West Florida", from Spanish control in 1810, and its subsequent annexation by the United States. In 1819 the United States and Spain negotiated the Adams–Onís Treaty, in which the United States purchased the remainder of Florida from Spain. The treaty was ratified in 1821.