A county island is an unincorporated area within a county, usually, but not always, surrounded on all sides by another incorporated area, such as a city. On maps, these geopolitical anomalies will form jagged or complex borders and 'holes' in the city limits. Generally found more frequently in the western United States, county islands form in areas of expansion when previously smaller cities will annex and incorporate more land into their jurisdiction. If residents or landowners in a particular unincorporated area do not vote to incorporate with the surrounding city, the area remains unincorporated. The formation of a county island usually follows stages where it will come into being on the edge of an incorporated area, and as more territory is incorporated, be cut off from the rest of the unincorporated area within the county. These areas are not, by definition, exclaves because they are simply unincorporated within a surrounding city.