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.
Territorial evolution of the United States
Desires for expansion into Spanish territories like Cuba led to the Spanish–American War in 1898, in which the United States gained Guam, Puerto Rico, and the Philippines, and occupied Cuba for several years. American Samoa was acquired by the United States in 1900 after the end of the Second Samoan Civil War. The United States purchased the U.S. Virgin Islands from Denmark in 1917. Guam and Puerto Rico remain territories; the Philippines became independent in 1946, after being a major theater of World War II. Following the war, many islands were entrusted to the U.S. by the United Nations, and while the Northern Mariana Islands remain a U.S. territory, the Marshall Islands, Federated States of Micronesia, and Palau emerged from the trust territory as independent nations. The last major international change was the acquisition in 1904, and return to Panama in 1979, of the Panama Canal Zone, a region of American sovereignty to build and run the Panama Canal. The final cession of power over the region was made to Panama in 1999.