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.
1810s
Spain would also lose Florida to the United States during this decade. First, in 1810, the Republic of West Florida declared its independence from Spain, and was quickly annexed by the United States. Later, in 1818, the United States invaded Florida, resulting in the Adams-Onís Treaty, wherein Spain ceded the rest of Florida to the United States.