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.
History of slavery in Florida
American settlers began to establish cotton plantations in northern Florida, which required numerous laborers, which they supplied by buying slaves in the domestic market. On March 3, 1845, Florida became a slave state of the United States of America. Almost half the state's population were enslaved African Americans working on large cotton and sugar plantations, between the Apalachicola and Suwannee rivers in the north central part of the state. Like the people who owned them, many slaves had come from the coastal areas of Georgia and the Carolinas. They were part of the Gullah-Gee Chee culture of the South Carolina Lowcountry. Others were enslaved African Americans from the Upper South who had been sold to traders taking slaves to the Deep South. By 1860, Florida had 140,424 people, of whom 44% were enslaved and fewer than 1,000 free people of color. Their labor accounted for 85 percent of the state's cotton production. The 1860 Census also indicated that in central Leon County (Tallahassee), which was the center both of the Florida slave trade and of Florida’s plantation industry (see Plantations of Leon County), slaves constituted 73% of the population. As elsewhere, their value was greater than all the land of the county. (References in History of Tallahassee, Florida#History of black Tallahassee.)