United States territorial acquisitions
West Florida was declared to be a U.S. possession in 1810 by President James Madison after the territory had declared its independence from Spain. Madison ordered the U.S. Army to take control. Six weeks later, the army entered and occupied the capital, St. Francisville, putting an end to the republic after 74 days of independence. Spain did not relinquish its claim to sovereignty (see West Florida Controversy) until ratification of the Adams–Onís Treaty. General Andrew Jackson personally accepted the delivery of West Florida from its Spanish governor on July 17, 1821.
West Florida Controversy
Previous to May, 1803, U.S. envoy Robert Livingston had contended that West Florida formed no part of Louisiana. However, the ambiguous third article of the treaty of St. Ildefonso lent itself to his purpose, although he had to adopt an interpretation that France had not asserted nor Spain allowed. Chambers arrives at what he calls the key to Mr. Livingston's sudden change of conviction concerning West Florida: "It had been and was the desire of the United States to acquire West Florida and the Island of Orleans. [James] Monroe had assented to the purchase of Louisiana instead. If Livingston could formulate a reasonable theory upon which the United States could base a claim to West Florida the glory would be his and his alone."