Around AD 150, at the height of the Roman Empire, its road network ran to about 299,171 kilometres, or roughly 186,000 miles. That is the total of Itiner-e, a research dataset of Roman roads published in 2025, and it is the network drawn on our map All Roads Lead to Rome.
A bigger network than we thought
The previous best estimate was 188,555 km (about 117,000 miles). Itiner-e adds more than 110,000 km to it, mostly secondary roads that earlier maps left out. Laid end to end, the network would wrap around the equator about seven and a half times.
|
Kilometres |
Miles |
| Whole network, c. AD 150 |
299,171 |
185,896 |
| Main roads (34.6%) |
103,478 |
64,298 |
| Secondary roads (65.4%) |
195,693 |
121,598 |
| Previous estimate |
188,555 |
117,163 |
How sure are we?
Less than you might think, and the dataset says so. Every one of its 14,769 road segments carries a certainty grade:
- Certain: about 2.7% of the length. The road’s exact course is known, from excavation or surviving remains.
- Conjectured: about 89.8%. Historians know a road existed between two places, but its exact line is inferred, usually from the landscape, later roads or old maps.
- Hypothetical: about 7.4%. A road probably existed, but the evidence is thin.
So when a map shows “every Roman road”, almost all of what you see is a careful reconstruction. Our map keeps that honesty: the legend draws certain, conjectured and hypothetical roads differently, following the Itiner-e grades.
Why the network mattered
Roman roads moved armies, officials, traders and the imperial post. Distances along them were marked by milestones, and itineraries listed the stations along each route. That is where the dataset’s name comes from: an itinerarium was a Roman road list.
See it on the wall
All Roads Lead to Rome draws the whole Itiner-e network on one sheet, with Latin place names from the Pleiades gazetteer and relief shaded from satellite elevation, in the manner of an 1889 atlas.
Figures from the Itiner-e static dataset (version 2024), CC BY 4.0. Miles converted at 1 mile = 1.609344 km.
