U.S. Territorial Acquisitions

Date

Territory

Area
(square miles)

Comment

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-OnĂ­s Treaty

1845

Texas

389,166

Annexation of independent republic

1846

OregonTerritory

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

1857

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 Enderburyislands

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