The once rich fur trade could not be replaced by a rich cotton trade until farmers replaced the nomadic Indians along the fertile lands of the river. The Creeks finally went into open war against the United States and were defeated by General Andrew Jackson at Horseshoe Bend in Alabama.

The Treaty of Ft. Jackson (1814), signed by the Creeks, ceded a large tract of land in southern Alabama and Georgia to the United States. At the close of the War of 1812, the British representatives in the area argued by letter with Benjamin Hawkins that the Treaty of Fort Jackson was not valid because the Treaty of Ghent, which ended the "Seven Years War" called for the status quo antebellum, i.e., that things were to go back as they were before the war.

Hawkins argued that the Treaty of Fort Jackson ante-dated the Treaty of Ghent. The Creeks preferred the British position. Louisiana, ceded to Spain in 1763 and retroceded to France by a servile Spain in 1800, was sold in 1803 by Napoleon to the United States.

The insistence of the United States upon trading with France hampered the efforts of the British and allied powers in their war against Napoleon (1797-1815), and the British made Florida a center of operations during the War of 1812. The British prepared to take formal possession at Pensacola but were repulsed by General Jackson in 1814.

The British also landed supplies at St. George Island preparatory to fortifying the area of the future Ft. Gadsden, but, by landing and removing the same troops repeatedly, they created the impression of a force much larger. British agents also evacuated Pensacola with Indian allies and captured slaves of the Spanish and of the Forbes Company and fortified what was to become Ft. Gadsden.

Damage to Forbes property by British forces was the basis for another request for a land grant. Notice was sent, however, from the British fleet under Admiral Alexander Cochrane noted for his role in the Latin American wars of independence that the British were to withdraw.

After 1814, the area of the future Ft. Gadsden was armed by the British and used by Indians and runaway Negroes to harass United States settlers. A United States force under General Gaines from the Mississippi Territory and Commander Daniel Patterson, U.S.N., destroyed the fort. A single hot shot hit the magazine and the fort exploded. The Seminoles, seceders from the Creeks, who occupied Apalachee territory, also fought the United States bitterly in 1817-1818.

British trading activities continued in the area. The Indians ignored the Treaty of Fort Jackson, and General Andrew Jackson went to the area of Ft. Gadsden and built the fort, naming it for its designer. Ft. Gadsden was manned from 1818 to 1821-1822. General Jackson then proceeded to the Suwanee River, and failing to capture the Seminoles, continued to St. Marks, where he hung two British subjects for inciting the Indians against U. S. citizens.

When he received information that hostile Indians were in Pensacola, he took Pensacola on the grounds that the Spanish were encouraging the Seminoles. Pensacola and St. Marks were temporarily returned to the Spanish, but John Calhoun, Secretary of War, advised General Gaines that U. S. troops were to stay at Fort Gadsden. In 1821, Florida was transferred to the United States with Jackson as Governor of Florida.