Territories of the United States are one type of political division of the United States, administered by the U.S. government but not any part of a U.S. state. These territories were created to govern newly acquired land while the borders of the United States were still evolving. Territories can be classified by whether they are incorporated (part of the United States proper) and whether they have an organized government (through an Organic Act passed by the U.S. Congress). The organized incorporated territories of the United States existed from 1789 to 1959, through which 31 territories applied for and won statehood. The U.S. had no unincorporated territories (also called "overseas possessions" or "insular areas") until 1898, but continues to control several of them today.

Incorporated and unincorporated territories
An organized territory is a territory for which the United States Congress has enacted an Organic Act to formally set forth its system of government. Such territories can be incorporated or not, but only non-incorporated organized territories have existed since the Territory of Hawaii was admitted as a U.S. state in 1959.

Organized and unorganized territories
The provisions of an Organic Act typically include the establishment of a Bill of Rights for the territory, as well as the framework of a tripartite government. Such a territory is said to be organized. Historically, an organized territory differed from a state in that although the organic act allowed for limited self-government, a territory had no constitution and ultimate authority over the territory was held not by the territorial government but by the United States Congress. Some contemporary organized territories have constitutions, but such constitutions are distinct from state constitutions in that they do not qualify the territory for becoming a state of the union.

Form of government
See also: Organized incorporated territories of the United States
The first organized territory in the United States was the Northwest Territory, organized in 1787 by the passage of the Northwest Ordinance, which is the prototype for subsequent organic acts. In the following century and a half, 29 other territories were organized at one time or another. Historically, the organization of a territory by the passage of an organic act was typically a prelude to statehood. All of these were incorporated territories, meaning that they were fully part of the United States, though that distinction did not arise until the first non-incorporated territories were gained following the Spanish-American War in 1898.

Incorporated organized territories
In the current lexicon of the United States political insular areas, a "commonwealth" is considered a special case of an organized territory. At present, there are two—Puerto Rico and the Northern Mariana Islands. Neither of these, however, is an incorporated territory.
Additionally, Guam and the United States Virgin Islands are organized territories, but they are neither incorporated nor considered commonwealths. On the other hand, American Samoa is formally considered an unorganized territory, though it is self-governing under a 1967 constitution.

Non-incorporated organized territories
Most of the historic territories of the United States, including all the ones that eventually became U.S. states, were incorporated organized territories, that is, incorporated territories for which Congress established a local civil government. The distinction between unincorporated territories and incorporated territories did not arise until the 20th century, following the acquisition by the United States of possessions arising from the Spanish-American War, including the Philippines, Guam, and Puerto Rico. Previously, the United States had acquired territory only through annexation, with all territories being de facto incorporated territories.
The distinction between incorporated and unincorporated territories was clarified in the 1937 United States Supreme Court case People of Puerto Rico v. Shell Oil Co., in which the Court determined that the Sherman Antitrust Act, which had referred only to "territories," applied to Puerto Rico even though it was not an incorporated territory of the United States. See also: Insular Cases, and Guano Islands Act.
In the contemporary sense, the term "unincorporated territory" refers primarily to insular areas. There is currently only one incorporated territory, Palmyra Atoll, which is not an organized territory. Conversely, a territory can be organized without being an incorporated territory, a contemporary example being Puerto Rico.
See organized incorporated territories of the United States and unincorporated territories of the United States for timelines.

History

Classification of current U.S. territories
none since 1959

Incorporated organized territories

Palmyra Atoll is privately owned by the Nature Conservancy and administered by the U.S. Department of the Interior. It is an archipelago of about 50 small islands about 1.56 square miles (4 km²) in area that lies about 1,000 miles (1,600 km) south of Honolulu. The atoll was acquired by the United States in the 1898 annexation of the Republic of Hawaii. When the Territory of Hawaii was incorporated on April 30, 1900, Palmyra Atoll was incorporated as part of that territory. However, when Hawaii became a state in 1959, Palmyra Atoll was explicitly separated from the state, remaining an incorporated territory but receiving no new organized government. Incorporated unorganized territories

Guam
Northern Mariana Islands (commonwealth)
Puerto Rico (commonwealth)
United States Virgin Islands Unincorporated unorganized territories

Classification of former U.S. territories & administered areas
See Organized incorporated territories of the United States for a complete list.

Former incorporated organized territories of the United States

Line Islands (?–1979): Disputed claim with United Kingdom, all U.S. claims ceded to Kiribati upon its independence.
Panama Canal Zone (1903–1999): sovereignty returned to Panama under the Torrijos-Carter Treaties; the U.S. retains a military interest
Philippine Islands (1902–1935); Commonwealth of the Philippines (1935–1946): Full independence in 1946.
Phoenix Islands (?–1979): Disputed claim with United Kingdom, all U.S. claims ceded to Kiribati upon its independence. Former unincorporated territories of the United States (incomplete)

Puerto Rico (April 11, 1899-May 1, 1900): civil government operations began
Philippines (April 11, 1899-July 4, 1901): civil government operations began
Cuba (April 11, 1899-May 20, 1902): sovereignty granted as Republic of Cuba
Guam (April 11, 1899-July 1, 1950): civil government operations began Former unincorporated territories of the United States under military government

Trust Territory of the Pacific Islands (1947–1986): included the Compact of Free Association nations (Marshall Islands, Federated States of Micronesia, and Palau) and the Northern Mariana Islands
Ryukyu Islands (1952–1972): returned to Japanese control, included some other minor islands under the Agreement Between the United States of America and Japan Concerning the Ryukyu Islands and the Daito Islands. Other zones

Political divisions of the United States
Territorial evolution of the United States
Historic regions of the United States
Organized incorporated territories of the United States
Unincorporated territories of the United States
Insular area
Unorganized territory
Incorporated territory
Enabling act (United States)
Hawaiian Organic Act