Many parts of the United States were first territories with the plan that they would someday become states.

　　Former territories include Oklahoma, which became a state in 1907; New Mexico and Arizona, which became states in 1912; and Hawaii and Alaska, which became states in 1959.

　　But in the late 19th and early 20th century, some areas came under the U.S. government's control without any plan for them to ever become states. Today many of these areas operate as territories under the Office of Insular Affairs in the Department of the Interior.

　　PUERTO RICO: About 3.5 million people live in Puerto Rico. The Department of the Interior does not administer this territory. More people live in Puerto Rico than all of the other territories combined. The island has a larger land area than either Rhode Island or Delaware. If Puerto Rico were a state, it would have the 29th-largest population in the country.

　　In a special election in 2012, a majority of Puerto Ricans said they did not want to remain a territory. But while voters clearly rejected their territorial status, it was not clear if they wanted the island to become a state, an independent country, or a country with a formal relationship with the United States. Almost three years ago, Congress approved a federally supported referendum that would pay for Puerto Rico to hold another vote to say clearly what they want.

　　The current governor does not want Puerto Rico to become a state, so he has not taken steps to create a ballot for the referendum.

　　U.S. VIRGIN ISLANDS: The U.S. Virgin Islands (USVI) is about 65 kilometers east of Puerto Rico. It is about twice the size of the District of Columbia. The USVI has three main islands: St. Thomas, St. John and St. Croix. About 103,000 people live in the territory.

　　GUAM: American military bases occupy more than one-quarter of the island of Guam, which is about 550 square kilometers. About 161,000 people live on Guam. It is the largest and southernmost of the Mariana Islands, which are in the northwestern Pacific Ocean.

　　NORTHERN MARIANA ISLANDS: There are 15 islands in the Commonwealth of the Northern Mariana Islands. The commonwealth includes all islands in the Mariana Archipelago except Guam. About 52,000 people live on the three main islands (Saipan, Rota and Tinian) in the commonwealth.

　　AMERICAN SAMOA: About 54,000 people live in American Samoa, which has three major islands, two small islands and two coral atolls. The area covers about 199 square kilometers. That is a little larger than Washington, D.C.

　　American Samoa is the southernmost U.S. territory and the only inhabited territory south of the Equator. It is in the Oceania group of islands in the South Pacific Ocean, about halfway between Hawaii and New Zealand.

　　U.S. citizens can travel to all of the U.S. territories without a passport, except American Samoa. That is because American Samoa has its own immigration agency and sets its own rules. American Samoa has its own constitution as do Puerto Rico and the Northern Mariana Islands.

　　UNINHABITED TERRITORIES: There are eight uninhabited atoll, coral reef or island U.S. territories in the Pacific. They are Palmyra Atoll, Baker Island, Howland Island, Jarvis Island, Johnston Atoll, Kingman Reef, Midway Atoll and Wake Atoll.

　　There are three uninhabited island U.S. territories in the Caribbean: Bajo Nuevo Bank, Navassa Island and Serranilla Bank. Other countries dispute the U.S. control of some of these territories.