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List of area code overlays


An area code overlay is a North American area code that is assigned to the same numbering plan area (NPA) as at least one other area code. Overlay codes are determined and regulated as part of the North American Numbering Plan to increase the number of available telephone numbers in a province, state or region.

The North American Numbering Plan Administration maintains the definitive list of overlay plans of area codes in the United States. The majority of overlay plans in North America have occurred since 1995. The process has been driven by fragmentation of numbering resources by a growing number of competitive local exchange carriers.

Various new area codes are planned or proposed. A few overlay implementations (557 MO, 564 WA, 689 FL, 975 MO) have been suspended, often because wasteful allocation of telephone numbers has been mitigated by number pooling or other conservation efforts.


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