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.
Florida Panhandle
The Florida Panhandle, an informal, unofficial term for the northwestern part of the U.S. state of Florida, is a strip of land roughly 200 miles long and 50 to 100 miles wide (320 km by 80 to 160 km), lying between Alabama on the north and the west, Georgia also on the north, and the Gulf of Mexico to the south. Its eastern boundary is arbitrarily defined. The terms West Florida and Northwest Florida are today generally synonymous with the Panhandle, although historically West Florida was the name of a British colony (1763–1783), later a Spanish colony (1783–1821), both of which included modern-day Florida west of the Apalachicola River as well as portions of what are now Alabama, Mississippi, and Louisiana.