History of Florida
In 1810, parts of West Florida were annexed by proclamation of President James Madison, who claimed the region as part of the Louisiana Purchase. These parts were incorporated into the newly formed Territory of Orleans. The U.S. annexed the Mobile District of West Florida to the Mississippi Territory in 1812. Spain continued to dispute the area, though the United States gradually increased the area it occupied.Seminole Indians based in East Florida had been raiding Georgia settlements, and runaway American slaves were their allies; Negro Fort, an abandoned British fortification in the far west of the territory, was manned by both Indians and blacks. The United States Army would lead increasingly frequent incursions into Spanish territory, including the 1817–1818 campaign against the Seminole Indians by Andrew Jackson that became known later as the First Seminole War. The United States now effectively controlled East Florida. Control was necessary, according to Secretary of State John Quincy Adams, because Florida had become "a derelict open to the occupancy of every enemy, civilized or savage, of the United States, and serving no other earthly purpose than as a post of annoyance to them." 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.
Tombigbee District
The British held West Florida until 1779–81, late in the American Revolutionary War, when it was captured by Spanish forces under the command of Bernardo de Gálvez. It formally became a Spanish possession with the 1783 Treaty of Paris, which also ended the American Revolution. This caused a boundary dispute between the United States (US) and Spain, with the U.S. claiming that the boundary between its territory and West Florida was at the 31st parallel north and Spain claiming it at 32 degrees 28 minutes of north latitude. Spain held the Tombigbee settlements until the Pinckney's Treaty in 1795, in which they agreed to the boundary at the 31st parallel north in return for other concessions by the US. It was ratified in the United States Senate on March 7, 1796 and by Spain on April 25, 1796, being proclaimed on August 3, 1796. The treaty stipulated that both countries would participate in a joint expedition to mark the agreed-upon boundary; President George Washington selected Andrew Ellicott as commissioner. The survey was completed in early 1800, although American settlers had already been pouring into the area since the proclamation of the treaty.