Central Office Code Assignment Records

From this page, you may download central office code assignments for the US and its territories by clicking on the appropriate link in the table below.

Clicking on a link will cause a compressed (zipped) file to be downloaded to your computer. The data is sorted by State, and then by NPA-NXX. These files require the use of a ZIP decompression utility on your computer in order to extract the data files.

For the text (ASCII, tab delimited) files, for each region of the country there are two links, one containing utilized codes, and one containing available codes. The file contains either all of the available or all of the utilized central office codes in the region.

CO Code (Prefix) Status

Region States Download File
Central - North IA, IL, IN, KY, MI, MN, OH, WI available codes (zip)

utilized codes (zip)
Central - South AL, AR, LA, MO, MS, TN, TX available codes (zip)

utilized codes (zip)
Eastern - Atlantic PR, VI available codes (zip)

utilized codes (zip)
Eastern - North CT, MA, ME, NH, NJ, NY, PA, RI, VT available codes (zip)

utilized codes (zip)
Eastern - South DC, DE, FL, GA, MD, NC, SC, VA, WV available codes (zip)

utilized codes (zip)
Western - North CO, ID, KS, MT, ND, NE, NV, OR, SD, UT, WA, WY available codes (zip)

utilized codes (zip)
Western - Pacific AK, AS, GU, HI, NN available codes (zip)

utilized codes (zip)
Western - South AZ, CA, NM, OK available codes (zip)

utilized codes (zip)
All States   utilized codes (zip - 1.4mb)

CO Code (Prefix) Status - Excel Spreadsheet Files

Region States Download File
Central AL, AR, IA, IL, IN, KY, LA, MI, MN, MO, MS, OH, TN, TX, WI Download (zip)
Eastern CT, DC, DE, FL, GA, MA, MD, ME, NC, NH, NJ, NY, PA, PR, RI, SC, VA, VI, VT, WV Download (zip)
Western AK, AS, AZ, CO, CA, GU, HI, ID, KS, MT, ND, NE, NN, NM, NV, OK, OR, SD, UT, WA, WY Download (zip)

Note that these files represent information contained in the NANPA code assignment system, and do not include all of the information required for routing and billing.

CO Codes Field Definitions

Field Definition
State Abbreviation Standard two character abbreviation.
NPA-NXX Area Code and Prefix
OCN Operating Company Number
Company Name Full Company Name; Company Names are enclosed with quotes if they contain special characters.
Rate Center 10 character abbreviation for the Rate Center in which the code is assigned.
Future Effective Date (EffectiveDate) The future date when a new code will be in service (for new codes only). Once the effective date is reached, this date will no longer appear.
VC VC indicates codes that are vacant; they are available for assignment to a service provider.
AS AS indicates codes that are assigned to a service provider.
PR PR indicates codes that are protected for a split; that is, these codes are assigned in the old or the new NPA and can not be assigned in the other NPA until after the end of permissive dialing.
RV RV indicates codes that have been reserved by a service provider. The identity of the service provider is considered proprietary information and will not be shown.
UA UA indicates codes that are unavailable for assignment. These codes include, but are not limited to, test and special use codes (e.g., 958, 959, 555, time), N11 and other unique codes (e.g., 976, 950), codes set aside for pooling, and codes with special dialing arrangements (e.g., 7-digit dialing cross NPA boundary).
Assigned Date (AssignDate) Date the code was assigned to the service provider by NANPA. This field is populated only for those codes assigned from January 2001 on.
Initial or Growth (Initial/Growth) Initial is the first geographic NXX code assigned at a unique switching entity or point of interconnection for a service provider. Growth is a code assigned to a switching entity or point of interconnection subsequent to the assignment of the first code, for the same purpose as a code that was previously assigned for a service provider to the same switching entity or point of interconnection.

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