Pont Saint-Martin

Is it worth the trip?

As a stop, yes, without hesitation. This is a complete Roman bridge, not a stump of masonry, it is free, and it sits in the town centre beside a car park, a bus stop and cafés (OpenStreetMap). Pont-Saint-Martin is the first town of the Aosta Valley as you come up from Piedmont (the Region), so it costs almost nothing to break a drive up the valley here.

As a destination on its own, it is one structure: half an hour on the bridge, under it and in the museum covers it. If you are heading on up the valley, it belongs to the same Roman road as Augusta Praetoria – Aosta, and the Pont d’Aël is another Roman bridge of the valley (en.wikipedia).

Getting there

The bridge is in the centre of Pont-Saint-Martin, next to the main square (the Region); the museum is on Piazza IV Novembre. There are several car parks within about 120 m, one of them free, and a bus stop on the square, 84 m away (OpenStreetMap). The town is on the Pont-Saint-Martin–Aosta bus line; the railway was temporarily closed when the Region’s tourism site was read in October 2026, with replacement buses running (lovevda.it).

The bridge itself has no ticket and no opening hours. The Region lists the museum as open every day of the year from 09.00 to 18.00, free of charge (balteus.lovevda.it, read 21 October 2026). The Ministry of Culture’s listing shows it closed every day, so if the museum matters to you, phone ahead (+39 0125 804843).

History

The bridge carried the Roman road through the Aosta Valley, which divided at Augusta Praetoria (Aosta) for the passes of the Great and Little St Bernard into Gaul (it.wikipedia); the road was built up step by step in the second and first centuries BC as Rome expanded across the Alps (de.wikipedia). The bridge standing today most likely dates from the time of Augustus, who took Aosta in 25 BC, refounded it as the colony of Augusta Praetoria and had the local road system renewed. Its foundations of dressed stone blocks differ clearly from the rubble facing above them, which has led to the suggestion that an earlier bridge of similar span stood here from 141 or 120 BC and did not last, the concrete technique of the time not yet being mature (de.wikipedia). The Region’s own page gives the date as uncertain, around 120 BC or 25 BC.

What makes it unusual is the arch. It is one of the few flat, segmental arches known from antiquity: its centre lies 5.8 m below the springing points, so the vault describes 144 degrees of a circle rather than a half-circle. A flatter arch saves material but pushes harder sideways, so it needs strong abutments in the banks. The arch ring of 71 voussoirs is only about 1.03 m thick. The engineer Colin O’Connor treated the ratio of ring thickness to span as the key figure for a stone arch bridge: Roman builders usually kept it above 1/20 on large bridges, and here it drops to 1/34, unmatched among the more than forty Roman bridges he examined (de.wikipedia). The nearness of the Pont de Pierre in Aosta, on the same stretch of road and also Augustan, may point to the segmental arch having become a local practice (de.wikipedia).

Local legend says the devil built the bridge in one night for Saint Martin, in exchange for the soul of the first to cross it; the saint threw a piece of bread over and sent a hungry dog across first. The story is still a theme of the town’s carnival, which ends with a devil burned in effigy under the bridge (the Region).