North American Numbering Plan, NPA/NXX's

As of April 1999, there were 105291 NPA/NXX's (area code plus exchanges) registered for use in the USA and Canada. These prefixes are served by "central offices" located at some 24644 "wire centers". It is at these wire centers that "local loops" to customers are terminated and branch circuits to other offices originate.

This map shows the distribution of wire centers in the USA and Canada. A given NPA/NXX pair will map to exactly one of these points. Each of these points may serve from 1-30 exchanges. The map is a gnomonic projection: straight lines are great circle paths, angles are true. [Click the image for a larger map.]

A 3.7 MB April 1999 ascii database of these exchanges and wire centers is available on line. The format is:

       npa nxx  lat   lng   u st city
       201 200 40.71 074.07 L NJ Jersey City 
       201 202 40.85 074.04 W NJ Little Ferry 
       201 203 40.79 074.48 W NJ Morristown 
       (L and W mean land or wireless use)

A 3.5 MB January 1998 database is kept here also. At that time there were 95543 NPA/NXX's served by 24269 wire centers.

For related information, see:

North American Numbering Plan Administation - includes Area Code maps
Traffic Routing Administration - where you can purchase official information databases.
TELECOM Digest & Archives

These databases and maps were prepared by the author, P. Dykstra, June 1999.

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