Archaeologists have created the most detailed digital map of the Roman Empire's roads around AD 150, revealing a network nearly 300,000 kilometres long. This open dataset, called Itiner-e, boosts previous estimates by almost 60 percent and is available for public exploration online. The project combines satellite imagery, topographic data, and historical records to trace realistic paths across the empire.
The Itiner-e project, led by researchers including Tom Brughmans at Aarhus University in Denmark, addresses a long-standing gap in Roman archaeology. 'It emerged from enormous frustration,' Brughmans says. 'It’s like the most enigmatic topic in Roman archaeology. We even have proverbs that say, ‘All roads lead to Rome’. So why on Earth can’t I download all the Roman roads? Where are they?' By incorporating evidence from numerous studies, the team produced a map of the road network as it likely appeared in AD 150, assigning confidence ratings to each segment based on source quality.
The dataset estimates the total length at 299,171 kilometres, far exceeding the 188,555 kilometres in the Barrington Atlas of the Greek and Roman World. However, precise locations are available for only 2.8 percent of the network—within 50 metres in mountains and 200 metres on flat terrain. Brughmans attributes this to funding challenges for excavations and historical overbuilding of major routes.
Catherine Fletcher at Manchester Metropolitan University, who was not involved, notes that Roman roads were not always straight. 'Straight wasn’t always cheap or practical, especially through mountainous terrain,' she says. 'Often, where there was a pre-existing route in place, the Romans would adapt it rather than build anew.'
This enhanced mapping could reshape understandings of historical events like the spread of early Christianity, mass migrations, and pandemics, all facilitated by the roads. Fletcher highlights their underappreciation: '[It’s like that] famous scene in Monty Python, where they’re talking about what the Romans did for us, and they go, ‘And the roads… Well, obviously the roads! The roads go without saying’.' The work is published in Scientific Data (DOI: 10.1038/s41597-025-06140-z).