Area codes for a specific area can be found on AllAreaCodes.com and AreaCode.org. As of June 2015, both websites offer area code information by both number or location. Both websites offer the option of searching for an area code for U.S. and Canadian cites.
Halfway down the All Area Code home page, under Area Code Look Up, you can obtain location by area code or area code by location. The specific area covered by that area code is located by entering the three-digit area code and tapping search tab. A map of the area displays showing the general area covered by that area code. Further down the page, the area code and specific exchanges are listed along with the corresponding city. For a fee, this website has options to look up by complete phone number or use of a reverse directory. A printable map of the area is available through this site.
The Area Code website lists the codes by numerical order and includes the state and major cities serviced by that code. Tapping on the area code brings up a map of the covered area and its surrounding area codes. The left side of the page lists major and secondary cities in alphabetical order along with the county and state.