CPL has a free list of area codes by state in alphabetical order. All Area Codes, however, has an area code list that lists cities by numerical order.
All Area Codes offers one page that contains two places to find area codes. The side of the page contains a list of area codes, while the instant look up option allows users to search by area code or city. The column has tabs for each set of 100 area codes, starting with the 200s and going through the 900s.
CPL lists the states in alphabetical order. Area codes for each state are given in numerical order. It also provides an approximation of how many people have a particular area code. Users can also opt to purchase a full guide from CPL.