24.5
PDI
10 mi
DISTANCE
3,782 ft
GAINED
7.1 %
AVG. GRADE
FULL CLIMB STATS
INTRO
Semnoz climbs 16.1 km (10.0 mi) from the city of Annecy in France's Haute-Savoie, gaining 1,153 m (3,782 ft) at an average grade of 7.1% to reach 1,658 m (5,438 ft) near the Crêt de Chatillon. It's rated Hors Categorie, and the summit plateau looks straight down onto Lake Annecy - one of the best-known lake views in the French Alps.
The lower kilometers climb steadily through forest above the city before the road opens up on the higher slopes, with sweeping views back over the lake. The grade builds toward the top rather than easing off - the steepest half-kilometer, just past the 15 km mark, averages 13.7%, a tough finish after already climbing for over an hour.
Semnoz earned a permanent place in Tour de France history in 2013, when Stage 20 finished atop the mountain for the first time - Colombian climber Nairo Quintana won the stage in a preview of his overall podium finish that year. The mountain was also on the 1998 route, though that stage was neutralized amid rider protests during the Festina doping scandal. We rode Semnoz ourselves on a May morning and passed several other cyclists on the road before 9 a.m. - even on a weekday, this is one of Lake Annecy's most popular local climbs. See our Routes in the Area tool for other climbs near Annecy.
PLAN YOUR ROUTE
We've partnered with Sherpa-Map.com to bring you the best route planning tool. With a PRO Membership you can use this climb as a reference when creating your route. Semnoz averages 7.1% over 16.1 km (10.0 mi) from Annecy, gaining 1,153 m (3,782 ft) from 521 m (1,710 ft) up to 1,658 m (5,438 ft) near the Crêt de Chatillon.
The grade is far from steady. The steepest 100 meters average nearly 20%, and the steepest quarter-mile still holds 14.0%. The single toughest stretch comes late: the half-kilometer beginning around the 15 km mark averages 13.7%, arriving well after an hour of climbing for most riders. Even the steepest 5 km block of the route holds at 9.0%, so there's no easy section to recover on once the real climbing starts.
Expect the final kilometers to be the hardest of the day, both because of the grade itself and because they come on top of everything below.
Roadway: The D41 (Route du Semnoz) is fully paved and well maintained for its entire length - a popular enough local road that Grand Annecy keeps it in good repair.
Traffic: Traffic is moderate on the lower slopes near Annecy and picks up on weekends and in summer as day-trippers head up to the Semnoz plateau for the views; it thins out considerably on weekday mornings.
Parking: Starting from Annecy itself avoids any parking question, but note that Grand Annecy is phasing in paid parking at Semnoz starting winter 2026-2027 - about 1 euro per hour at the summit lot, with roadside parking along the D41 expected to follow gradually. Check current signage before leaving a car streetside.
The steepest sections come late in the climb, after more than an hour of steady effort, so a compact crankset (34/50) with a wide-range cassette (30-32t low gear) is a good call for most riders.
Annecy has full services at the base, but there's little beyond a summer-season snack stand near the top, so carry enough water and food for the full 16.1 km (10.0 mi) ascent. The exposed upper plateau can be noticeably cooler and windier than the lakeside city below.
Before heading out on any cycling adventure check out our Things to Bring on a Cycling Trip and use our interactive check list to ensure you don't forget anything.
Annecy is one of the great lakeside base towns in the French Alps, and Semnoz is the local mountain literally in its backyard - a popular training climb for riders staying in town rather than a destination requiring its own trip.
Beyond Semnoz, Annecy also puts several other major climbs within reach for a multi-day trip: Mont du Chat, the four approaches to Col du Grand Colombier, and Col de la Forclaz, which starts from the opposite shore of the lake.
The climb is rideable spring through fall; the summit road can hold snow into late spring in a heavy winter, so check conditions before an early-season trip.
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carlinguernsey
This climb basically starts from the center of Annecy with many good hotels, restaurants, and services. Much of the climb is in forest without much to see (other than the informational signs each kilometer). The last few k are much more open with some views. Try to do this one on a clear day to take advantage of the panoramic views from the top. There are some services at/near the top, but not much on the way up.
