Except for Palmyra Atoll, all of these islands are unincorporated, unorganized territories of the United States. As of 2019 , none of the islands have any permanent residents. The U.S. Territory of Palmyra Island is an incorporated territory, separated in 1959 from the rest of the former incorporated Territory of Hawaii when Hawaii became a state. The only human population consists of temporarily stationed scientific and military personnel. The 2000 census counted 315 people on Johnston Atoll and 94 people on Wake Island.
There has been no modern indigenous population, except at the 1940 census. In 1936 a colonization program began to settle Americans on Baker, Howland, and Jarvis, but all three islands were evacuated in 1942 as a result of World War II.
The islands are grouped together as a statistical convenience. They are not administered collectively, nor do they share a single cultural or political history beyond being uninhabited islands under the sovereignty of the United States. They are all outside of the customs territory of the United States and have no customs duties. Except for Midway Atoll, the Pacific islands are surrounded by large Exclusive Economic Zones and are within the bounds of the Pacific Remote Islands Marine National Monument.
They are collectively represented by the ISO 3166-1 alpha-2 code UM. The individual islands have ISO 3166-2 numerical codes.
The Internet country code top-level domain (ccTLD) ".um" has historically been assigned to the islands; however, the .um ccTLD was retired in January 2007.
ISO introduced the term "United States Minor Outlying Islands" in 1986. From 1974 until 1986, five of the islands (Baker Island, Howland Island, Jarvis Island, Palmyra Atoll and Kingman Reef) were grouped under the term United States Miscellaneous Pacific Islands, with ISO 3166 code PU. The code of Midway Atoll was MI, the code of Johnston Atoll was JT, and the code of Wake Island was WK. Prior to 1986, Navassa Island, along with several small islands in the Caribbean Sea—that are no longer under U.S. sovereignty—were grouped under the term United States Miscellaneous Caribbean Islands, with FIPS country code BQ.
The populated Stewart Islands, called Sikaiana and now effectively controlled by the Solomon Islands, are not included in official lists of U.S. Minor Outlying Islands. In 1856, the Kingdom of Hawaii Privy Council and King Kamehameha IV voted to accept their voluntary cession. The Kingdom later became the Republic of Hawaii, all of which was annexed by the United States in 1898. In 1959, the resulting federal U.S. Territory of Hawaii, excluding only Palmyra Island and Midway Island, became a U.S. state. Residents of the Stewarts, who are Polynesian like the native Hawaiians rather than Melanesian, claimed to be citizens of the United States since the Stewarts were given to King Kamehameha IV in 1856 and were part of Hawaii at the time of the United States' annexation in 1898. The U.S. federal and Hawaii state governments informally accept the recent claim of the Solomon Islands over the Stewarts, and the United States makes no official claim of sovereignty.
Most of the islands in the U.S. Minor Outlying Islands are closed to the public—visitors to islands such as Jarvis Island need a permit; Palmyra Atoll is open to the public, but there is no easy way to reach it.