US Area Codes By State Explained

The US started out with just 77 area codes in 1947 and since then the number has increased to over 300. US Area Codes are managed by the North American Numbering Plan Administrator (NANPA). The NANPA is a part of the US Federal Communications Commission (FCC). Below is our list of US area codes by state.

Toll-Free Area Codes

In the US and its territories, area codes are assigned to specific geographic areas. Overlays can be introduced to create additional numbers in high-population areas. The overlay area code system allows two or more area codes to be assigned to the same geographical area. However, each individual telephone number only has one area code.

Overlays and splits are especially common in busy cities, including, San Francisco, San Diego, Austin, New York City, Detroit, Chicago, Los Angeles, Dallas, Oklahoma City, Philadelphia, Jacksonville, Houston and many more

The North American Numbering Plan (NANP) was created in 1947 by AT&T with the Bell System to standardize dialing practices across the US, Canada, and some Caribbean nations. It also helped with long distance calling. The NANP area code system was developed to unify the various numbering systems in use at the time. It came into public use in 1951.

There are 7 toll-free area codes that do not represent a specific geographic region.

Parts of A US Phone Number

Phone numbers in the US generally consist on 10 or 11 digits. First comes the single digit country code that is normally only used when calling from outside the country. The next three digits of a phone number are called the Area/NPA (Numbering Plan Area) code. Area codes are three-digit numbers that represent specific geographical areas. The next three digits are called the Central Office Code (NXX). The final four digits is the subscriber number.