This is a list of United States territorial acquisitions, beginning with American independence. The treaty with the United Kingdom in 1783 defined the original borders of the United States.

• The Louisiana Purchase, completed 1803, was negotiated by Robert Livingston during the presidency of Thomas Jefferson; the territory was acquired from France.

• Red River Basin, acquired in 1818 by treaty from Great Britain

• Florida Purchase, made in 1819 from Spain, under the administration of John Quincy Adams

• Texas Annexation of 1845: In 1836 the Republic of Texas voted to be annexed by the United States. Despite the fact that Mexican leader Antonio López de Santa Anna warned that annexation would be "equivalent to a declaration of war against the Mexican Republic," President John Tyler signed a treaty of annexation with Texas in April 1844, causing the Mexican War. After James Polk, a strong supporter of territorial expansion, won the presidency, but before he took office, Congress approved the annexation of Texas on February 28, 1845. On December 29, 1845, Texas became the twenty-eighth state.

• Oregon Country, ceded to the U.S. by the Great Britain in 1846 under the Oregon Treaty, the two countries had jointly controlled the area since 1818

• Mexican Cession lands were a product of the Mexican War and the subsequent Treaty of Guadalupe Hidalgo, signed February 2, 1848. In this treaty, Mexico gave the U.S. parts of what is Texas, Colorado, Arizona, New Mexico and Wyoming, and the whole of California, Nevada and Utah and recognized the Rio Grande as Texas' Southern border. The United States paid Mexico $15 million. In addition, the United States agreed to pay claims made by American citizens against Mexico, which amounted to more than $3 million.

• Gadsden Purchase of 1853, United States purchased a strip of land along the Mexican border for $10 million, now in New Mexico and Arizona. This territory was later used for the southern transcontinental railroad.

• Alaska Purchase from Russia in 1867.

• Hawaii, annexed 1896 upon the request of a government made up mainly of American settlers who had overthrown the Kingdom of Hawaii.

• Puerto Rico, Guam and the Philippines, taken from Spain after the Spanish-American War in 1898. The Philippines became an independent nation in 1946.

• American Samoa, occupied in 1899, made a formal territory in 1929.

• U.S. Virgin Islands, bought from the Danish Crown for $25 million on January 17, 1917 during the First World War. Virgin Islands inhabitants became American citizens in 1927.

• Marshall Islands, Federated States of Micronesia, Northern Mariana Islands and Palau, occupied by the United States during World War II, formalised under the UN trusteeship system in 1947. The Marshall Islands became independent in 1986 and Palau in 1994.

See also

• United States territory
• Political divisions of the United States
• Regions of the United States