Area code

An area code is officially known as a numbering plan area and is part of a Telephone numbering plan. Here is an area code listof the North American telephone area codes in effect for the North American Numbering Plan. Note that an area code cannot start with a 0 or 1 because each digit represents either feature codes or the North American long distance code. Prior to 1995 all area codes had either 0 or 1 as the middle digit; all new codes from 1995 to present use 2 through 8.

The N9X area codes are reserved for the event that the area codes might need to be expanded to 4 digits (by inserting a 9 in the second digit's place, creating "N9XX," thus making any "N9X" area code impossible), although there is no definite plan for implementing this, only one industry forum recommendation.

Numbers of the form N11 (in other words ending in "11") are reserved for special usage such as 9-1-1 and cannot be used as Area Codes, the NANP's emergency telephone number, which connects the caller automatically to the nearest Police/Fire/EMS dispatcher (N11 is not a valid exchange for the same reason).