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.
Colonial history of the United States
In 1763, Spain traded Florida to Great Britain in exchange for control of Havana, Cuba, which had been captured by the British during the Seven Years' War. Florida was home to about 3,000 Spaniards at the time, and nearly all quickly left. Britain occupied Florida but did not send many settlers to the area, and control was restored to Spain in 1783 by the Peace of Paris which ended the American Revolutionary War. Spain sent no more settlers or missionaries to Florida during this second colonial period. The inhabitants of West Florida revolted against the Spanish in 1810 and formed the Republic of West Florida, which was quickly annexed by the United States. The United States took possession of East Florida in 1821 according to the terms of the Adams–Onís Treaty.