Global Policy Forum

US Territorial Acquisitions


Area (square miles)
1783 Former colonies 892,135 Treaty of Paris of 1783 following military victory
1803 Louisiana Purchase 827,987 Purchased from France for $15 million, including assumed claims
1819 Florida (East and West) 72,101 Purchased from Spain for $5 million in assumed claims under Adams-Oní­s Treaty
1845 Texas 389,166 Annexation of independent republic
1846 Oregon Territory 286,541 The Oregon Treaty with Great Britain
1848 Mexican Cession 529,189 Purchase from Mexico following military victory; $15 million plus 3.25 million in assumed claims
1853 Gadsden Purchase 29,670 Purchased from Mexico for $10 million

Baker Island,Howland Island,Jarvis Island

.5, .6, 1.7 Unincorporated territory claimed under Guano Act of 1856
1858 Johnston Atoll 1.1 Unincorporated territory annexed under Guano Act of 1856; chemical weapon disposal site
1867 Alaska 591,000 Purchased from Russia for $7.2 million; statehood 1959
1867 Midway Islands 2 Annexation of unoccupied area
1898 Hawaiian Islands 6,450 Annexation of independent republic; statehood 1959
1898 Philippine Islands 115,800 Purchased from Spain following military victory; independent in 1946
1898 Puerto Rico 3,508 Annexed following military victory over Spain
1898 Guam 209 Annexed following military victory over Spain
1899 American Samoa 76 Annexed in settlement with Britain and Germany
1899 Wake Island 3 Annexation of unoccupied area
1903 Panama Canal Zone 553 Leased from Panama for $10 million, plus $250,000 annually; ceded to Panama in 1999
1917 Virgin Islands 136 Purchased from Denmark for $25 million; currently an organized, unincorporated U.S. territory under jurisdiction of Office of Insular Affairs of the Dept. of the Interior
1922 Kingman Reef .4 Annexed 1922; later airline refueling; currently uninhabited; National Wildlife Refuge
1938 Kanton and Enderbury Islands 3.5, 3.0 Joint occupation with Britain; independent as Kiribati in 1979
1947 Mariana Islands 179 United Nations Trust Territory; self-governing as Northern Mariana Islands
1947 Caroline Islands 500 United Nations Trust Territory; 1986 most islands adopt commonwealth status as Federated States of Micronesia
1947 Marshall Islands 70 United Nations Trust Territory; 1979 self-governing; 1986 independent as Republic of the Marshall Islands

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