Produced: on or before 5th calendar day monthly
Current Release: February 2, 2024
Distribution Frequency: monthly or quarterly (issue date: January, April, July, October)
Distribution Format: Internet download
This mapping is based on the geography of the NPA NXX Rate Center and the ZIP Code boundaries which yields a true representation of the coverage areas.
NPA NXX numbering resources are assigned by Rate Centers. Rate Centers are the regulated geographic service areas that telecom carriers provide service to and because their boundaries are relatively stable it is possible to compare them to USPS postal carrier routes to determine what NPA NXX combinations are used in specific Zip Codes.
|Numbering Plan Area (NPA) Code. An NPA, also known as a telephone area code, is the first three digits of a 10-digit North American Numbering Plan (NANP) telephone number in the form NXX-NXX-XXXX, where N represents any one of the numbers 2 through 9 and X represents any one of the numbers 0 through 9. Valid numeric range for NPA codes is 200 through 999.
|Central Office Code (COC). The COC, commonly called the telephone exchange or prefix, is the second three digits (NXX) of a 10-digit NANP telephone number in the form NXX-NXX-XXXX, where N represents any one of the numbers 2 through 9and X represents any one of the numbers 0 through 9. Valid numeric range for NXX codes is 200 through 999.
|5-digit United States ZIP Code.
|2-character United States Postal Service abbreviation for the state, or territory of the city and Rate Center location.
|United States Postal Service recognized name for the city or locale identified by the current ZIP code.
|10-character industry standard abbreviated name of the Rate Center (or service) where the NPA NXX is assigned.