United States territorial acquisitions

Census Bureau map depicting territorial acquisitions and dates of statehood.

This is a list of United States territorial acquisitions, beginning with American independence.

Note that this list primarily concerns land acquired from other nation-states; the numerous territorial acquisitions from American Indians are not listed here. One perspective on this state of affairs is that the land was claimed as the territory of one European colonial power or the other, but it was owned by the Native peoples who resided there, created a tiered system of possession. (For example, under this standard, Kansa Indians would be considered French nationals pre-1803, and American nationals post-1803.) For an in-depth exploration of Native American land cessions, researchers may refer to Eighteenth Annual Report of the Bureau of American Ethnology to the Secretary of the Smithsonian Institution, 1896-1897 by Charles C. Royce, which can be viewed online at the Library of Congress' American Memory Website.

The 1783 Treaty of Paris with Great Britain 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. A small portion of this land was ceded to Great Briatain in 1818 in exchange for the Red River Basin.

West Florida was declared by President James Madison to be a US possesion in 1810.

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. The Sabine Free State was also acquired under this treaty.

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 this 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-American 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. The San Juan Islands were claimed and jointly occupied by the U.S. and Great Britain from 1846-1872 due to ambiguities in the treaty. Arbitration led to the sole US possesion of the San Juan Islands since 1872.

Mexican Cession lands were a product of the Mexican-American 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.

The Guano Islands Act of 1856 provided for U.S. claims to unnocupied islands. Baker Island, Howland Island, and Navassa Island were annexed in under its provisions in 1857. Johnston Atoll was claimed by the US and Hawaii in 1858; the US claim became undisputed in 1896 after the annexation of Hawaii. Midway Atoll was discovered and claimed in 1859 and formally annexed 1867. Kingman Reef was annexed in 1922.

Alaska Purchase from Russia in 1867.

Chamizal from Mexico from 1852-1873 due to course change of the Rio Grande River. The territory was mostly retroceded to Mexico by treaty in 1963.

Hawaii, annexed 1898 upon the request of a government made up mainly of American settlers who had overthrown the Kingdom of Hawaii. With Hawaii came the Palmyra Atoll which had been annexed by the U.S. in 1859 but later abandoned, then later claimed by 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.

Wake Island, annexed in 1899

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

Tutuila Island and Aunuu Island ceded by their chiefs in 1900, then added to American Samoa.

Manu'a Islands, annexed in 1904, then added to American Samoa.

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.

Swains Island, annexed in 1925 (occupied since 1856), then added to American Samoa.

Jarvis Island, reclaimed in 1935, previously annexed in 1858, but abandoned in 1879.

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. Micronesia and the Marshall Islands both achieved independence in 1986 and Palau in 1994, via Compacts of Free Association.

The Boundary Treaty of 1970 transfered 2702.9 acres of Mexican territory to the U.S.. In exchange, the U.S. ceded 2087.87 acres to Mexico, including the town of Rio Rico, Texas.

See also