Florida
Florida had become a burden to Spain, which could not afford to send settlers or garrisons. Madrid therefore decided to cede the territory to the United States through the Adams–Onís Treaty, which took effect in 1821. President James Monroe was authorized on March 3, 1821 to take possession of East Florida and West Florida for the United States and provide for initial governance. Andrew Jackson, on behalf of the U.S. federal government, served as a military commissioner with the powers of governor of the newly acquired territory for a brief period. On March 30, 1822, the U.S. Congress merged East Florida and part of West Florida into the Florida Territory.
By the early 1800s, Indian removal was a significant issue throughout the southeastern U.S. and also in Florida. In 1830, the U.S. Congress passed the Indian Removal Act and as settlement increased, pressure grew on the U.S. government to remove the Indians from Florida. Seminoles offered sanctuary to blacks, and these became known as the Black Seminoles, and clashes between whites and Indians grew with the influx of new settlers. In 1832, the Treaty of Payne's Landing promised to the Seminoles lands west of the Mississippi River if they agreed to leave Florida. Many Seminole left at this time.
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.