Listed below is a collection of all the US area codes that we have details for, along with some unique facts about them that most people don't know.
Did you know? Area codes cannot begin with 0 or 1. Why? 0 and 1 are already designated for unique billing purposes within the PSTN (public switched telephone network). Dialing 0 first tells the phone company you want operator-assisted billing (e.g. calling collect). Dialing 1 first tells the phone company that you need to be billed for a long distance call.
Did you know? The second digit of an area code originally had to be 0 or 1. That was changed when the rapid growth of cellular phones began exhausting the available pool of numbers within the existing area codes. Today, the second digit can be any 0-9 integer.
Did you know? The term "area code" is actually short for Numbering Plan Area, which is often abbreviated as NPA in technical literature.
Did you know? A private sector company in cooperation with government agencies, Neustar, oversees the development of new area codes through the North American Numbering Plan Administration.
District Of Columbia