This presentation describes the cartographic evolution of National Park Service tourist maps for Yellowstone National Park over 100 years. It examines maps from 1913 to the present and correspondence/reports that shed light on how map styles changed based on preferences of park officials and tourists. Key map styles included early NPS maps, Blue Lake maps, single color maps, shaded relief maps, mini-folders, and modern unigrid maps. The evolution was not linear and reflected feedback on improving usefulness and readability.