This article describes a comprehensive geographic information system of Third-Republic France: the TRF-GIS. It provides annual nomenclatures and shapefiles of administrative constituencies of metropolitan France from 1870 to 1940, encompassing general administrative constituencies (départements, arrondissements, cantons) as well as the most significant special administrative constituencies: military, judicial and penitentiary, electoral, academic, labor inspection, and ecclesiastical constituencies. It further proposes annual nomenclatures at the contemporaneous commune level that map each municipality into its corresponding administrative framework along with its population count. The 901 nomenclatures, 830 shapefiles, and complete reproduction material along with primary sources of the TRF-GIS database are available at https://dataverse.harvard.edu/dataverse/TRF-GIS. regions and subdivisions), judicial constituencies (courts of appeal and of first instance), penitentiary constituencies, electoral constituencies (circonscriptions), academic constituencies (academies), labor inspection constituencies, and ecclesiastical constituencies (dioceses). The TRF-GIS further proposes annual nomenclatures at the contemporaneous commune level that map each municipality into its corresponding administrative framework along with its population count. The construction of TRF-GIS shapefiles uses a methodology different to the manual vectorization of georeferenced historical maps. 7, 13, 16, 17 It first reconstructs the administrative framework contemporaneous communes were embedded in, then aggregates these units into relevant constituencies using modern communes shapefiles. Despite some limitations, this method offers substantial advantages: not only it provides more precise results than existing outputs, but, more importantly, it also enables to circumvent the fundamental problems of non-existence of annual historical maps and of time and resource investments associated with manual vectorization methods. By providing a comprehensively-curated common frame of reference that encompasses all aspects of the French society, the TRF-GIS will help create the conditions for a better understanding of the dramatic socioeconomic changes that France underwent during the seven decades that lasted the Third Republic. Methods General methodology The underlying structure of the TRF-GIS builds on three datasets that are available under open licensing (Figure provides an overview of the construction logic of the TRF-GIS): 1. INSEE's Codes Officiel Géographique (COG) nomenclatures. 18 INSEE's annual COGs provide the official nomenclature of communes and of general administrative constituencies in the geography of a given year. Existing communes are uniquely identified through a five-digit coding scheme, which first two digits correspond to a commune's département and last three to its number within the département, generally assigned in ascending alphabetical order. For instance, the commune of Allonne in the département of Oise (60) holds INSE...