In law, a region of land is unincorporated if it is not a part of any municipality. To "incorporate" in this context means to form a municipal corporation, i.e., a city or similar. Unincorporated, in turn, implies no city and hence no city, town, village, or other municipal government.

Thus, an unincorporated town is usually not subject to or taxed by a city government. However, such regions are generally administered by default as a part of larger territorial divisions such as: township, county, state, province, canton, or country.

In the United States, unincorporated regions tend to be fairly rare in the densely-poulated northeastern states, but are very common in the western states, like California. The state of Hawaii takes the concept to its logical conclusion: it has no incorporated cities (except for the City and County of Honolulu) and all its "towns" are administered at the county level.

In the context of the United States insular areas, the word "unincorporated" means that the territory has not been formally and irrevocably incorporated into the United States. (See: incorporated territory.) Unincorporated insular areas are therefore potentially subject to being sold or otherwise transferred to another power, or, conversely, being granted independence. However, neither fate seems likely to occur in the foreseeable future to the five remaining major unincorporated U.S. insular areas, American Samoa, Puerto Rico, Guam, the U.S. Virgin Islands, or the Northern Mariana Islands.