Lac Nègre

Lac Nègre sits at 2,354 metres above sea level in the commune of Valdeblore, within the Vésubie valley in France's Mercantour National Park, in the Alpes-Maritimes department. It is generally regarded as the largest body of water in this stretch of the Maritime Alps, making it one of the signature hiking destinations in the area.

How big is the lake, and where does its name come from?

The lake stretches roughly 530 metres by 260 metres, covering just under 14 hectares. It is a glacial lake, occupying a rock basin carved out by an ancient glacier. Its name — from the French word for "black" — points to the dark tone of the water, produced by reflections off the surrounding granite landscape combined with the lake's considerable depth, which runs to several dozen metres.

How do you get to Lac Nègre?

Most hikers start from Saint-Martin-Vésubie, driving the D89 toward Boréon and continuing past the reservoir to the Salèse car park, one of the entry points into Mercantour National Park. From there, the route follows the GR 52 long-distance trail, which links Saint-Dalmas-de-Valdeblore with Menton over its full course. The path climbs the right bank of the Salèse valley toward the Col de Salèse before branching off to the lake itself. The round trip typically takes between 5.5 and 6 hours and involves about 650 metres of elevation gain — a moderately demanding outing best suited to hikers with some mountain experience.

Does the lake have a notable history?

Lac Nègre has an unusual chapter in its past. In 1958, army engineers from the 7th Engineering Regiment used the lakebed for a seismic experiment, detonating a large quantity of explosives to measure how shock waves travel through the earth's crust. According to local mountain guides, the blast sent a plume of water several metres into the air.

What rules apply inside the national park?

Because the lake lies within the core zone of Mercantour National Park, strict conservation rules apply. Picking plants, bringing dogs, and setting up camp are all prohibited. Visitors are expected to stay on marked paths and respect the quiet of this high-altitude environment, home to wildlife that depends on minimal disturbance.

FAQ

How high up is Lac Nègre? The lake sits at an altitude of 2,354 metres.

Is it really the largest lake in the area? Yes — it is widely considered the largest body of water in this part of Mercantour National Park, with a surface area of nearly 14 hectares.

How long does the hike take? From the Salèse car park, following the GR 52 trail, the round trip usually takes 5.5 to 6 hours, with around 650 metres of elevation gain.

Can you camp near the lake? No. The area falls within the national park's core zone, where camping is banned and other conservation restrictions apply.

Why is the lake called "Nègre"? The name refers to the dark colour of its water, caused by reflections from the surrounding granite terrain and the lake's substantial depth.