Is there an area code registry available online?

AllAreaCodes.com provides access to U.S. based area codes categorized by city, state or cartographic representation. It is also a resource for Canadian area code look-up and international country codes.

AllAreaCodes.com provides a reverse phone number look-up feature as well as search by area code and city features. It contains information on how area codes are allocated and the meanings of the other seven numbers. For instance, All Area Codes explains that certain prefixes are reserved for special purposes, such as the 800 area code. It is reserved for toll-free calling where the called party is charged instead of the calling party.