Unorganized Territory

In the United States, an unorganized territory is a region of land without a "normally" constituted system of government. This does not mean that the territory has no government at all or that it is unclaimed territory. In practice, such territories are always sparsely populated.

Historically, the term "unorganized territory" was applied to an area in which there was no effective government control of affairs on a day-to-day basis, such as the former U.S. territories where the government exerted only transient control when its forces were actually present. In modern usage it indicates an area in which local government does not exist, or exists only in embryonic form. However the area is still, at least in theory, governed by the nation of which it forms part, or by a smaller unit of that nation.

These lightly governed regions were common in the 19th century during the growth of United States. Large tracts such as the Louisiana Territory, Missouri Territory and the Oregon Country were established by Congress. Later, a portion of a territory would organize and achieve the requirements for statehood, leaving the remainder "unorganized".

Unorganized territories, as defined by the U.S. Census Bureau, occur in 10 minor civil division (MCD) states (Arkansas, Indiana, Iowa, Louisiana, Maine, Minnesota, North Carolina, North Dakota, Ohio, and South Dakota) where portions of counties are not included in any legally established MCD or independent incorporated place. The U.S. Census Bureau recognizes such separate pieces of territory as one or more separate county subdivisions for statistical purposes. It assigns each unorganized territory a descriptive name, followed by the designation "unorganized territory". Unorganized territories were first used for statistical purposes in conjunction with the 1960 census.

...
Wikipedia