I love this table

http://faculty.weber.edu/kmackay/chronological_list_ofexpansion.htm

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 & 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