List of NANP area codes

The North American Numbering Plan (NANP) divides the territories of its member countries into Numbering Plan Areas (NPAs), each identified by a three-digit code commonly called area code.

The rules for numbering NPAs do not permit the digits 0 and 1 as the leading digit of an area code, which also applies for central office codes. 0 has been used traditionally for operator-assisted telephone calls, and the digit 1 was traditionally ignored in switching equipment as a leading digit, because it could not be distinguished reliably from intermittent loop disconnections when subscribers operated telephones. NPAs with 9 as the second digit are reserved for future format expansion. Area codes with the last two digits matching, such as 322 and 755, are considered easily recognizable codes (ERC), and are also reserved; existing assignments are the toll-free codes 800, 888, 877, 866, 855, and 844.

200: easily recognizable code (ERC)

201: New Jersey (Hackensack, Jersey City, Hoboken, Bayonne, Ridgewood, Ramsey, and most of northeastern New Jersey)

202: Washington, D.C. (all)

203: Connecticut (Bridgeport, Danbury, New Haven, Waterbury, and southwestern Connecticut)

204: Manitoba (all). Overlaid by 431 in November 2012.

205: Alabama (Birmingham; Tuscaloosa, and parts of western and central Alabama)

206: State of Washington (Seattle, all of Bainbridge, Mercer, and Vashon islands, Burien, Des Moines, Lake Forest Park, Normandy Park, Sea-Tac, Shoreline, Tukwila, and some small unincorporated areas adjacent to these. Also, parts of Woodway and Edmonds)

...
Wikipedia