A new open-access academic resource, Itiner-e , makes the most detailed digital road map of the Roman Empire available to the public. The database, compiled by an international team, covers 299.171 kilometers of roads and offers an unprecedented overview of the road system that underpinned Roman mobility, the economy, and administration.
The dataset reconstructs the network at its peak, around 150 AD , when the Empire numbered approximately 55 million inhabitants and stretched from Britain to Egypt and Syria. Its publication coincides with its release in the journal Scientific Data (Nature Portfolio) and the launch of the interactive map for online viewing.
What is Itiner-e and why does it matter?
Itiner-e nearly doubles the coverage of previous resources (from 188.555 to 299.171 km) by integrating previously poorly documented regions and adjusting the routes to the actual terrain, instead of resorting to simplified straight lines. The result is high-resolution mapping that facilitates comparative analyses on an imperial scale.
The project is led by Pau de Soto and Adam Pažout (Autonomous University of Barcelona) along with Tom Brughmans (Aarhus University), and is conceived as an open, free, and updatable resource . Each researcher can add new data while retaining their authorship, which reinforces its collaborative nature and long-term usefulness.
Within the Iberian Peninsula, the dataset adds sections and improves accuracy in Spain and Portugal , with particular attention to classic routes such as the Via Augusta and the VÃa de la Plata . This level of detail will allow for a more rigorous exploration of how these roads shaped trade routes, military itineraries, and regional mobility in Western Europe.
Beyond logistics, the road network facilitated the exchange of ideas and beliefs and contributed to the spread of historical diseases. The map's resolution opens the door to computational studies on connectivity, transport costs , and administrative control in the ancient world.
How the map was built
The team has systematically identified routes based on archaeological reports and key historical sources such as the Antonine Itinerary and the Peutinger Table , as well as milestones and regional summaries . This documentary basis supports the location of the routes on the ground.
After identification, the routes were georeferenced using modern and historical topographic maps, satellite imagery, and other remote sensing data, and then manually digitized in GIS. This approach reveals that the paths cross mountains through winding passes and follow natural corridors, increasing spatial accuracy compared to previous solutions.
Itiner-e is interdisciplinary and collaborative by design: it integrates contributions from specialists in multiple countries and disciplines, and allows for the addition or correction of information with traceability. The repository offers open access and maintains unique identifiers for each section to facilitate its reuse in research.
In total, the network is organized into 14.769 segments and distinguishes between 103.478 km of main roads (34,6%) and 195.693 km of secondary roads (65,4%). This classification helps to analyze the imperial network structure in relation to the local and regional mobility network.
Key figures, level of certainty, and regional scope
The team specifies the level of security for each section: approximately 2,7% of the network has a well-documented location; about 89,8% has sufficient, though less precise, evidence; and around 7,4% responds to hypotheses in contexts with less documentation.
Quality varies by region, combining representativeness and reliability of sources. The Iberian Peninsula , southern France, and the Mediterranean Levant show above-average levels, while areas of the middle Danube or inland regions of Anatolia require further research to refine mapping.
In Spain, the improved resolution allows for tracking routes that cross mountain ranges with realistic curves, detecting forks in the road, and relating roads to nearby urban centers and archaeological sites . This approach provides a more robust context for discussions about road continuity and historical landscapes.
The applications are numerous: from connectivity and cost models to studies on military expansion, trade, demography, and disease transmission. The repository, accessible at itiner-e.org , facilitates cross-referencing data with historical sites and other databases for reproducible research.
Among the next steps, the consortium is working to incorporate maritime and river routes and record timelines, in order to observe how the network changes over time. In addition to the publication in Scientific Data , the study's DOI ( 10.1038/s41597-025-06140-z ) and a video illustrating the diversity of the roads, from paved tracks to desert trails, can be consulted .
With cartography that quadruples the detail of many previous resources and an explicit focus on uncertainty , Itiner-e is consolidating itself as a reference tool for studying ancient mobility in Europe and the Mediterranean; a robust starting point for new questions that, with open and collaborative data, will allow us to refine how the network that backbone the Empire was built, used and evolved .