As of April 1999, there were 105,291 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.

A 3.7 MB April 1999 ascii database of these exchanges and wire centers is available on-line. In addition, a 3.5 MB January 1998 database is also available. At the time the 1998 database was created, there were 95543 NPA/NXX’s served by 24269 wire centers.

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)

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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