ABSTRACT The Great War of 1914-1918 marked important developments in the evolution of military cartography. While recent research has examined these developments in the context of the European belligerent armies, including those of the British, Italians, and Germans, little research has explored the mapmaking efforts of the American forces that participated in the closing months of the conflict. This paper examines how the Army- and Corps-level headquarters of the American Expeditionary Force (AEF) in France used tactical maps to visualize spatial information and control the operations of subordinate forces on the battlefield to better understand how these novel mapmaking processes developed. The research draws upon archival records—including the AEF's maps and official documents—to understand how the AEF acted as a cartographic system that collected, transmitted, mapped, and distributed spatial information. The research indicates that the AEF mapmakers learned from the cartographic techniques of the other allied armies to develop a form and language of cartography that was distinct to the American army in France. These results reinforce the conclusions of other scholars that have argued that the Great War marks an important point in the evolution of military cartography.