North American Area Codes are prefixed to a phone number to assist in routing phone calls in North America. The North American Numbering Plan (NANP) dictates the regional and non-geographic area codes assigned to signatory countries. The United States, Canada, some Caribbean countries, and all US territories are covered by the plan.
There are 317 geographic area codes in the United States and an additional 18 non-geographic area codes totalling 335 US area codes.
What's confusing to people not familiar with the North American Numbering Plan is that many countries share the +1 prefix, whereas most countries around the world have their own country calling code. This means that +1 prefixed area codes are spread out amongst 25 countries including the United States
Canada has 40 geographic area codes and two non-geographic area codes bringing the total number of area codes dedicated to use in Canada to 42 (there is also toll-free).
NANPA is the organization charged to run the North American Numbering Plan (NANPA) by the FCC. In NANPA terminology area codes are called NPA's, short for Number Plan Areas. For the rest of us, we just call them area codes.
NANPA publishes two reports that show where area codes are distributed to:
- Geographic NPAs (area codes) In Service Sorted by Number
- Non-Geographic NPAs (area codes) In Service
There are currently 25 countries that are members of NANPA. The US makes up the majority of the numbers (335/380) and California has the most numbers of any state. Canada has the second most dedicated area codes at 42.
Twilio has 306 US area codes available to use on the Twilio platform.