Students of the history of cartography are invited to submit papers for the 2020 Ristow Prize competition. Undergraduate, graduate, and first-year postdoctoral students of any nationality are eligible to compete. Papers must be in English, not exceeding 7500 words, and should be submitted digitally as a PDF document to kaparker18th@gmail.com by 1 June 2020. Appropriate illustrations, especially maps, are encouraged. The winning essay will receive a cash prize of $1000 and will be published in The Portolan, the journal of the Washington Map Society. The prize, named in honor of the late Dr. Walter W. Ristow, is sponsored by the Washington Map Society of Washington, D. C. For more information, including a list of previous winners, go to the website www.WashMapSociety.org or contact Dr. Katherine Parker at kaparker18th@gmail.com.