Lac du Mont Cenis: A Detailed Look


Many of the great Alps roads owe much of their celebrity to cycling (Stelvio, Gavia, Galibier, Tourmalet, etc). Whereas Col and Lac du Mont Cenis is a famous passage that just happens to occasionally welcome a bike race.

My Friend Emily. Dam at left.

This post will map and detail eight rides in this beautiful location high on the French / Italian border:

  • Three road bike options including the best option via a little known alternate Italian route.
  • Four fantastic gravel rides well above the lake.
  • A super-high ride (2850m) that I have never ridden (yet!).
  • The bottom of the post includes some history and fun facts. Hannibal, Napoleon, Jules Verne, etc.

There are several great mountain bike routes well above the lake.

I’ll explain all the routes on this map. Note, some routes overlap, click on a route and it will appear “on top.”

Some Basic Facts:

At 2081 metres, The Col du Mont Cenis separates Lanslebourg, France with Susa, Italy. It is the border between the Cottian and Graian alps. Lac du Mont Cenis is at 1974 metres.

It has appeared 5 times in the Tour de France (’49, ’56, ’61, ’92, ’99). Twice from the much harder Italian side, and three times from the French side. The Giro climbed both sides in 2013.

The name Cenis derives from the french word “cendres” (ashes). Apparently there was an ancient forest fire that left the Col covered in ashes.

The summit/plateau with the lake has changed hands many times. Traditionally a part of the Kingdom of Savoie, occasionally part of Italy, from the 1860s usually the border between Italy and France. However, after World War Two, the plateau was ceded to France thus the border with Italy is currently a few kilometres down the Italian side, below the dam and lake.

French Hairpins that used to be Italian hairpins:

Italian Hairpins

Franco/Italian Hairpins

The Lake and Dam

There was always a small lake on the plateau said to be poisonous to fish. In the 1920’s, Italy built a small dam for hydro electricity, enlarging the lake. In the 1960s, France built a far bigger dam, increasing the lake size by a factor of ten. Currently, the hydro-electric power produced is shared between Italy and France. (Fish now thrive in the lake).

A cycling rule: If you see a dam, cycle over it.

The water level is often low early in the season, but it’s still beautiful.

Doreen and I would hike down the lake bed to the water.

The two main paved routes

The RED route on the map above.

French side

French side

Both sides of this climb are beautiful. Although the Italian side is a huge 25.5 kilometres long, versus less than 10 kms up the French side. The summits of each side are separated by a few kilometres of fairly level road that runs beside and above the lake. The valleys below on either side of the border are just full of great cycling climbs. (eg. Colle delle Finestre, Sestrières in Italy; Col de l’Iseran, Col du Galibier in France – to name but a few). For full details of both sides of the climb to Col du Mont Cenis see here.

Italian side

Hot Tip: Near the top of the French side of Mont Cenis is a turn off to the Col du Petit Mont Cenis. A well paved little road that gently climbs for 7 km before ending at the old 19th century French/Italian border. Simply Beautiful.

Road to Col du Petit Mont Cenis

Road to Col du Petit Mont Cenis

See here for details of the two main paved routes plus the extension to Col du Petit Mont Cenis.

The “Secret” 3rd paved route via Moncenisio

The BLUE route on the map above.

Starting near Susa, Italy is a tiny little road that hairpins up to the perched village of Moncenisio. From there, the route traverses to the main Italian route detailed above to the lake.

Don’t expect to see any cars on this tiny, hairpin-filled road

Emily on one of the great hairpins below the dam

See here for details of this great 3rd paved route. Note, in the linked post, after reaching the lake I do an optional gravel extension to the Ancien Fort de Ronce. The route descends the main paved road down the Italian side.

Fort de Ronce - 2286 metres

Fort de Ronce – 2286 metres

Unpaved Routes
Mont Froid (2822 metres) via Col de Sollières

The ORANGE route on the map above.

Mont-Froid at roughly 2800 metres

Starting from Termignon in the Haute-Maurienne, the route is gravel almost from the start. It’s full of hairpins, but of decent quality and rarely crazy steep. The climb is in a forest until above 2000 metres but even here and always above, I enjoyed fabulous views of the glacier across the valley.The route reaches the old Fort atop Mont Froid via Col de Sollières (2639 metres).

The border was moved in this region after WW2 (the French took the entire lake and beyond), but Mont Froid was a strategic placed French Fort and saw some action at the start and end of WW2, even changing hands twice in April 1945 just before the German retreat from the region.

at roughly 2600 metres. On way to Col de Sollières

The route then descends to Col du Petit Mont Cenis and then to the lake. See here for details of this ride. Note, from Col du Mont Cenis I descended on a brilliant unpaved old road.

Col de la Met (2735 metres)

The BLACK route on the map above.

View from Col de la Met

Much of the high gravel in the region are old military routes to forts, but the “road” to Col de la Meta is a ski-lift service road. I started in Lanslebourg, in the Haute-Maurienne. The south side of Col de l’Iseran (highest paved mountain pass in Europe) also begins here. I took the paved road almost to Col du Mont Cenis and then turned left onto this route. Full details here.

Almost there

Note, as part of this route I did a loop around the lake. You can cycle across the damn, but be aware it is gravel. As is the west side of the lake. You will likely not see a car on these stretches.

Gravel on west side

Pas de la Beccia (2717m) via Fort de la Turra

The PURPLE route on the map above.

Now that’s a view!

View of Lac du Mont Cenis from Pas de la Beccia

Perched strategically above Col du Mont Cenis and Lanslebourg, Fort de la Turra (2507 metres) was built in the 1890s by the French. It saw action in June 1940 during the Italian invasion. It was directly attacked by the Italians from Pas de la Beccia for several days. The Fort was surrounded but held out until the overall French surrender June 25th.

I started the climb in Lanslebourg at the start of the paved climb (details here) to Col du Mont Cenis. But I turned immediately onto an unpaved road that leads all the way to the Fort. Fabulous.

Last stretch to the fort:

The extension to Pas de la Beccia requires some walking, but the views of the lake are worth the effort. I descended over the top on a hiking trail eventually reaching the lake but I frankly don’t recommend this to cyclists. See here for full details of this ride.

Col du Clapier – 2480 metres

The Green route on the map above.

The paved road ends at Col du Petit Mont Cenis. But a gravel road / trail continues through another high valley to the Italian border at Col de Clapier. Keep an eye out for elephant footprints.

Above Col du Pt. Mont Cenis, heading to Col de Clapier

Many historians believe Hannibal crossed the Alps into Italy via Col de Clapier, high above Col du Petit Mont Cenis. See this blog post for a sensational ride up Mont Cenis, then to Col du Petit Mont Cenis, and then on unpaved roads and trails to Col de Clapier. It also includes riding around the Lake, on fun unpaved roads on far side.

Lac de Savine 2443 metres, near the Col du Clapier.

Ancien Fort de Malamot – 2850 metres

Finally, this climb is near the top of my “hope-to-ride” list. High above the west side of the lake, one can see some of the gravel hairpins up to yet another fort. Hopefully a summer project. If you’ve visited please let me know in the comments.

Some Mont Cenis History

(below was taken from a post I wrote a few years ago)

A Route for Armies and Pilgrims


In 218 B.C. The Carthagian General Hannibal led an army of nearly 40,000 soldiers and a few elephants over the Alps to attack Rome, beginning the Second Punic war. Historians today still debate which route Hannibal used to traverse the mountains. But leading theories include the region around Mont Cenis as one of three serious candidates. Of course the official tourist office is quick to mention Hannibal. In 1959 a slightly loopy British expedition successfully led a poor elephant over the Mont Cenis pass (most or all of Hannibal’s elephant did not survive their journey).

The Col du Mont Cenis has been a major route linking Italy and France for thousands of years. From approximately the 12th century, it supplanted Petit St. Bernard and Mont Genèvre as the most used passage.

In the 4th century, the Emperor Constantine the 1st would lead an army over the pass to attack Maxentius.

In 773, the Emperor Charlemagne would lead an army across Mont Cenis, as he attacked the Lombards. There is a famous French painting of the crossing.

The first hospice for travellers was built in 825 by Lothaire the 1st. Destroyed by Sarrasins in the 10th century, the hospice was rebuilt in the 13th century and maintained until the 18th century by Augustin monks. Significantly enlarged by Napoleon it was submerged in the 1960s when Electricité de France constructed a dam enlarging the lake. The foundations of the old hospice can still be seen when water levels are very low.

The Emperor Napoleon Builds A Road

Prior to the Napoleonic wars, the route was primarily a mule path used by pilgrims and merchants – although remains of a Roman road have been found crossing the nearby Col du Petit Mont Cenis.

In 1794, during the French Revolution – just before the Napoleonic wars – a French army crossed Mont Cenis to invade Italy.

After the Battle of the Nile in 1798, the British blockaded the French controlled Mediterranean ports and the Col du Mont Cenis became the major route into Italy. Napoleon – who crossed the pass himself at least twice – in 1803 ordered a road be built to improve the movement of supplies. Completed in 1810, it henceforth became possible for wheeled carts and carriages to make the traverse.

In 1811, the road linking Paris and Milan via Mont Cenis was completed. Traffic in that first year: 45,000 mules and 17,000 carriages.

The road was maintained by “cantonniers,” who were each responsible for a stretch of 5 kilometres or so and would live in little huts beside “their” piece of road. Many of these huts still exist – see here. For the interested here is a link to an 1811 rule book that the Cantonniers of Mont Cenis had to follow. They would be responsible for keeping the road maintained all year … including clearing snow in winter. Fascinating (to me at least).

Tunnels and Trains

From 1868 to 1871 a train service crossed over the pass, but was closed with the completion of — what was then — the longest tunnel in the world – tunnel ferroviaire du Mont-Cenis in 1871. But up high on the Italian side one can still little tunnels and avalanche protectors of the train line. In 1980, a new Fréjus tunnel opened allowing motor traffic to quickly pass between Italy and France, leaving the road over the mountain pass free of trucks and not too busy – good for cyclotourists.

Fréjus Tunnel museum, near old tunnel exit on French side.

Fréjus Tunnel museum, near old tunnel exit on French side.

the Tunnel of Mont Cenis was such a “wonder” in the 19th centure that in Jules Verne’s “Around the World in 80 Days” it was said that one could go around the world by using the Suez canal …. and The Fréjus Tunnel.

Miscellaneous Fun:

For more than a decade in the 1930s, Flambeau the post-dog assured daily mail service between the french Valley below and the summit of Mont Froid up above. Woof.

In winter, the French side becomes the longest Green (beginner) ski trail in Europe – called l’Escargot.

For the geologists see here and have fun (no idea what it’s all about).

Beside the lake is the Pyramide museum – recounting the history of Mont Cenis. Additionally, there are six old forts surrounding the lake.

Finally, here is a link to a video of coverage of stage 10 of the 1961 Tour de France, climbing Mont Cenis. You need to watch at the linked site, and it’s a little small, but quite fun. Click here.

OK, I’m thirsty. Now that you know a little about Mont Cenis, I suggest you pour yourself a beer and plan a visit. 🙂





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Happiest while cycling uphill.

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