Area Code Directory Information

Area codes are assigned to specific cities or areas within a state (or country) in order to distinguish local numbers that are identical but belong to different people or businesses. For example, the local number 123-4567 may belong to someone in both New York and California, so the 3-digit area code is necessary to distinguish which person you are going to call. In the U.S., if you are calling a different area code you must dial it in addition to the local number; this is considered a long-distance phone call. Depending upon the carrier and whether you're calling from a cellular or land phone, you may also need to dial a 1 prior to the area code.

Finding the Correct Area Code

Most often, phone directories and phone books will provide the area code in addition to the local numbers of people or businesses you wish to call. However, if you have no idea what the area code is, you can use an area code directory. An area code directory provides you with the codes found in a specific city or part of a state to help determine what the area code may be for that particular number. Of course, you may also use an online phone directory to find the complete number.

Information in an Area Code Directory

An area code directory will often provide every area code found within a particular state, as well as the boundaries of each code. Some directories will provide this with names of the covered and included cities, and others will do so with a visual map of the area.

You may also find the region that the area code belongs to, as well as the time zone. This will help you when making the call so you know whether you are calling during business hours.

Area code directories can also help you determine where a call is coming from. If you are receiving calls from a number you don't recognize and your caller ID shows an area code you aren't familiar with, you can use a directory to determine the specific locale it belongs to.

History of the Area Code

In the 1940's, AT&T and Bell Laboratories initiated the North American Numbering Plan (NANP) in the U.S. and Canada. The plan started with only 86 area codes, and they were three digits long. States with only one area code were given numbers with 0 as the middle digit, and those with more than one were given codes with a 1 in the middle. In addition, the population of an area determined the remaining digits. More residents in a city meant the area code digits were lower, and vice versa.

Even today, if you are placing a call to a location covered by the NANP, you must know the area code prior to dialing. You can always use an area code directory to ensure you have the correct code, or discover which region and area you have been receiving calls from.