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555 Line Numbers

The 555 NXX has been set aside in every geographic NPA (area code) for the purpose of reaching a wide variety of information services. This numbering resource is in the format 555 XXXX where the XXXX line number will be assigned to the subscriber offering the particular information service.

555 line numbers may be assigned for either national or regional (non-national) use. A national number is a unique line number in the 555 XXXX assigned to an entity for use in all or most of the geographic NPAs in the NANP Area. A number will be designated as a national number if it is to be used in at least 30% of all NPAs or states or provinces in the NANP Area. National numbers cannot be assigned to any other entity. A non-national number is a line number in the 555 NXX assigned to an entity for use in a specific geographic area or areas (NPAs, states, or provinces). A number will be designated non-national if it is to be used in fewer than 30% of NPAs or states or provinces. Non-national numbers are available for assignment to multiple entities, assuming those entities wish to use the non-national number in different geographic NPAs.

The following approved 555 NXX Assignment Guideline and related documents can be found on the CRTC website.

The Canadian Numbering Administrator (CNA) is participating in a North American Numbering Plan (NANP) initiative to return 555 line number resources to the North American Numbering Plan Administrator’s (NANPA’s) assignment pool. The NANPA has placed a moratorium on assignment of 555 line numbers. A copy of Planning Letter 483 can be found at:

There are currently no 555 numbers assignments in Canada.


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