Chronological List of United States Expansion Date   Territory Notes 1783   Former 13 colonies Treaty of Paris of 1783 following American Revolutionary War 1803   Louisiana Purchase Purchased from France for $15 million, including assumed claims 1819 Florida (East and West) Purchased from Spain for $5 million in assumed claims under Adams-Onís Treaty 1845 Texas Annexation of independent republic 1846 Oregon Territory The Oregon Treaty with Great Britain 1848 Mexican Cession Purchase from Mexico following American-Mexican War; $15 million plus 3.25 million in assumed claims 1853 Gadsden Purchase Purchased from Mexico for $10 million 1857 Baker Island Howland Island Unincorporated territory claimed under Guano Act of 1856; under the jurisdiction of the U.S. Fish and Wildlife Service 1857 Navassa Island Unincorporated territory claimed under Guano Act of 1856; under the jurisdiction of the U.S. Fish and Wildlife Service 1858 Jarvis Island Unincorporated territory claimed under Guano Act of 1856; under the jurisdiction of the U.S. Fish and Wildlife Service 1858 Johnston Atoll Unincorporated territory annexed under Guano Act of 1856; under the jurisdiction of the U.S. Fish and Wildlife Service 1867 Alaska Purchased from Russia for $7.2 million; Statehood 1959 1867 Midway Islands Unincorporated territory claimed under Guano Act of 1856; under the jurisdiction of the U.S. Fish and Wildlife Service 1898 Hawaiian Islands Annexation of independent republic; Statehood 1959 1898 Palmyra Atoll Acquired with Hawaii; under the jurisdiction of the U.S. Fish and Wildlife Service 1898 Philippine Islands Purchased from Spain for $20 millon following Spanish-America War; fully independent in 1946 1898 Puerto Rico Annexed following Spanish-America War; currently a self-governing commonwealth of the United States 1898 Guam Annexed following Spanish-America War; in 1950 became organized, unincorporated U.S. territory under jurisdiction of Office of Insular Affairs of the Department of the Interior 1899 American Samoa Annexed in settlement with Britain and Germany; currently an unorganized, unincorporated U.S. territory under jurisdiction of Office of Insular Affairs of the Department of the Interior 1899 Wake Island Annexation of unoccupied area 1903 Panama Canal Zone Leased from Panama for $10 million, plus $250,000 annually; ceded to Panama in 1999 1917 U.S. Virgin Islands Purchased from Denmark for $25 million; currently an organized, unincorporated U.S. territory 1922 Kingman Reef Annexed 1922; later airline refueling; currently uninhabited; National Wildlife Refuge 1947 Northern Mariana Islands United Nations Trust Territory; in 1986 became a self-governing U.S. commomwealth 1947 The Federated States of Micronesia United Nations Trust Territory; 1986 became a sovereign, self-governing republic 1947 Republic of Palau United Nations Trust Territory; in 1994 became a sovereign, self-governing republic 1947   Republic of the Marshall Islands United Nations Trust Territory; in 1986 became a sovereign, self-governing republic

Adapted from an article by Franklin K. Van Zandt U.S. Geological Survey Professional Paper 909, Boundaries of the United States and the Several States, pages 1-2, 1976.