This article explores the integration of GIS technology with urban historical studies, focusing on one case study from the 18th century, the project Historical atlas of the modern Rome. The methodology employed in this project allows for effectiveness and accuracy in historical data acquisition and integration, which enables refined analyses of socioeconomic and environmental phenomena. The approach outlined in this article allowed researchers from different disciplines—city historians, archaeologists, demographists, economists, and so on—to interpret urban phenomenologies according to different thematic keys. These interpretations were derived from archival sources that complement each other and offer diversified insights into the urban context. The techniques described in the article are based on methods of data acquisition and spatial analysis developed in a GIS environment by exploiting the effectiveness of this technology in the quantitative treatment of cartographic and documentary sources.