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.
Seminole
In 1819 the United States and Spain signed the Adams-Onís Treaty, which took effect in 1821. According to its terms, the United States acquired Florida and, in exchange, renounced all claims to Texas. Andrew Jackson was named military governor of Florida. As European-American colonization increased after the treaty, colonists pressured the Federal government to remove Natives from Florida. Slaveholders resented that tribes harbored runaway Black slaves, and more colonists wanted access to desirable lands held by Native Americans. Georgian slaveholders wanted the "maroons" and fugitive slaves living among the Seminoles, known today as Black Seminoles, returned to slavery.
After acquisition by the U.S. of Florida in 1821, many American slaves and Black Seminoles frequently escaped from Cape Florida to the British colony of the Bahamas, settling mostly on Andros Island. Contemporary accounts noted a group of 120 migrating in 1821, and a much larger group of 300 African-American slaves escaping in 1823, picked up by Bahamians in 27 sloops and also by canoes. They developed a village known as Red Bays on Andros. Federal construction and staffing of the Cape Florida Lighthouse in 1825 reduced the number of slave escapes from this site. Cape Florida and Red Bays are sites on the National Underground Railroad Network to Freedom Trail.