Enclaves are low-density areas surrounded by territory that is in the UA. Enclaves almost always consist of territory outside of any place (rarely are they incorporated places or CDPs); the surrounding territory may be in a place, or it may consist of nonplace territory. As with indentations, the inclusion of enclaves gives the UA a more regular appearance and simplifies data presentations. An enclave is included in the UA if it is five square miles or less in size and surrounded by territory that has an average density of at least 1,000 people per square mile. Both conditions must apply.
Exclaves occur where an outlying piece of a place is physically separated from the main part of the place by intervening territory that does not qualify for inclusion in the UA. The intervening territory consists of either territory outside of any place or—less frequently—in another place. Places with exclaves usually are incorporated places (most CDPs consist of one contiguous piece of territory). An exclave can never consist of territory outside of any place. Exclaves always are included in the UA when their parent place is in the UA; the criteria for density, continuous development, and road connection do not apply to exclaves.
Some incorporated places include large expanses of vacant or very sparsely populated territory that are essentially rural in character. In general, this situation results from (1) extensive annexation of adjacent undeveloped territory, (2) governmental consolidation of an incorporated place with an MCD or county, or (3) formation of a new incorporated place from several sparsely populated MCDs.
An incorporated place is considered to be an extended city if it contains one or more areas that:
- Are 5 square miles or more in size.
- Have a population density less than 100 people per square mile.
- Comprise at least 25 percent of the total land area of the place.
- Consist of 25 square miles or more.
The first two conditions, and either the third or the fourth, must apply.
