A list of Maryland zip codes can be found on the State of Maryland website through the Department of the Environment. The site houses an alphabetical, downloadable list of all zip codes in every region of the state.
The file also provides the county name and population for all of the cities in each respective zip code. According to the State of Maryland website, users must have Adobe Acrobat Reader to download and print the zip code file. The site provides a link to the Adobe website from which the user can download a free copy of Acrobat Reader software.