territory, in U.S. history, a portion of the national domain that is given limited self-government, usually in preparation for statehood. Territorial governments have been similar in form to those of the states, but have been subject to greater authority of the federal government. The Ordinance of 1787, adopted by the Congress of the Confederation of the United States to create the Northwest Territory, furnished the basis upon which territorial governments were later organized under the Constitution of the United States. The Louisiana Purchase of 1803 raised the problem of the relationship of the United States to newly acquired domains—a subject treated vaguely in the Constitution of the United States. The Supreme Court, however, established the right of Congress to set up territorial governments and to admit territories to the Union. With the rapid westward expansion of the United States in the 19th cent., and the acquisition of large portions of land through treaty, purchase, and war, Congress shaped territorial boundaries and prescribed government. Territorial governments usually have consisted of a governor, a bicameral legislature, a secretary to keep records, and a system of courts. A territory may be admitted to the Union as a state after its officers petition Congress for an enabling act, establish a constitution, and meet certain requirements (often regarding population) as set forth by the U.S. Congress. Congress itself may initiate such action. Except for the Thirteen Colonies and California, Kentucky, Maine, Texas, Vermont, and West Virginia, all the states went through a territorial stage before they were admitted to the Union. The affairs of territories were under the Dept. of State until 1873, when their supervision was given to the Dept. of the Interior. Present U.S. territories include the Virgin Islands, Guam, and American Samoa. In Canada and Australia a similar portion of the country not yet organized as a province or state is known as a territory.