Area codes can be found for free online via a number of different websites. All Area Codes provides a free listing of area codes for every location in the United States. Other websites that provide free area code listings are Area Code Locations and 50 States.
As of 2015, area codes are three-digit numbers that range from 201 to 989. The use of area codes initially began in large cities in the United States in 1947. They were initially assigned based on population; cities with a large population received an area code that was quick to dial on a rotary phone (for example, New York City was assigned a 212 area code).
The development of new towns, cities, fax machines and cell phones prompted the need for more area codes. Instead of adding more digits, the North American Numbering Plan Administration created a larger quantity of unique three-digit area codes.