The gabelle salt tax system was a cornerstone of the fiscal apparatus of the early modern French state. This article introduces a novel historical geographic information system (GIS) of this institution’s spatial organization as of the seventeenth century, drawing on an original 1665 manuscript map collection: Sanson’s Atlas des gabelles. Beyond presenting the dataset and documenting its construction methodology, we provide a detailed account of the functioning of the gabelle, situate the French case in comparative perspective, and illustrate how the availability of this fine-grained dataset expands the possibilities of empirical research in economic history, historical demography, and historical political economy of early modern France.