4.8
(48)
2,764
runners
136
runs
Jogging around Lac d'Ilay offers routes through a landscape shaped by glacial activity, featuring clear turquoise waters and imposing cliffs. The region is part of a larger "land of lakes" in the Jura, connected by natural canals and flowing into the Rivière du Hérisson. Trails often traverse protected natural environments, including Natura 2000 and Ramsar sites, highlighting rich biodiversity. The area's topography includes hills like the Pic de l'Aigle, providing elevated viewpoints over valleys.
Last updated: July 6, 2026
4.5
(2)
94
runners
12.0km
01:34
350m
350m
Hard run. Very good fitness required. Sure-footedness, sturdy shoes and alpine experience required.
55
runners
7.40km
00:49
50m
50m
Moderate run. Good fitness required. Mostly paved surfaces. Suitable for all skill levels.

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68
runners
10.6km
01:18
230m
230m
Hard run. Good fitness required. Sure-footedness, sturdy shoes and alpine experience required.
11
runners
5.59km
00:39
30m
30m
Moderate run. Good fitness required. Mostly accessible paths. Some sure footedness required.
6
runners
Moderate run. Good fitness required. Mostly accessible paths. Some sure footedness required.
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A superb hike with beautiful views of the seven waterfalls. It's quite crowded, so for a quieter return, you can take the GR 559 forest path back, which doesn't follow the water but is also magnificent in autumn!
0
0
The smaller of the two Maclu Lakes, with an easy hiking trail along its shore.
5
0
Small, rocky stretch of beach that you can climb down to, as well as good views of Lac Le Grand Maclu.
5
0
Water access with beautiful views of Lac Le Grand Maclu.
4
0
Small, privately owned botanical garden that can be visited by appointment.
5
0
Waterfall at the ruins of a former mill.
7
0
Larger waterfall Cascade Saut De La Forge with grotto and views directly onto the waterfall, as well as from above onto the water cascading down over smaller cascades.
7
0
Beautiful view near a crossroads of a small waterfall with cascades.
7
0
The Lac d'Ilay area offers a wide selection of running routes, with over 140 trails to explore. These range from easy lakeside loops to more challenging climbs, catering to various fitness levels.
Yes, there are several easily accessible paths perfect for beginners or a relaxed jog. For instance, the Lake Ilay loop from Le Frasnois is a moderate 5.6 km route that offers a scenic run around the lake with minimal elevation gain.
The terrain around Lac d'Ilay is diverse, shaped by glacial activity. You'll find a mix of forest paths, lakeside trails with clear turquoise waters, and some routes with more significant elevation changes leading to panoramic viewpoints. Trails range from smooth, easily accessible sections to more rugged paths, especially on routes climbing towards areas like the Pic de l'Aigle.
Absolutely. Many of the running routes around Lac d'Ilay are circular, allowing you to start and finish at the same point. A popular option is the Grand Maclu Lake – Petit Maclu Lake loop from La Chaux-du-Dombief, a moderate 9.3 km route that connects two of the region's beautiful lakes.
Yes, dogs are generally welcome on the trails around Lac d'Ilay. However, to protect the rich biodiversity of this Natura 2000 and Ramsar site, it's essential to keep dogs on a lead at all times and stay on marked footpaths. This helps preserve the natural environment and wildlife.
Many of the less strenuous lakeside loops are suitable for families. While specific 'family versions' are mentioned for hiking, routes with lower difficulty and shorter distances, such as parts of the lake loops, can be enjoyed by families jogging together. Always check the route details for distance and elevation to ensure it matches your family's ability.
The region is rich in natural beauty. You'll encounter the stunning turquoise waters of Lac d'Ilay and its neighboring glacial lakes, impressive cliffs, and the unique island 'motte' in Lac d'Ilay. For panoramic views, routes like the Pic de l'Aigle – Three Lakes Viewpoint loop from La Chaux-du-Dombief offer magnificent vistas over the Hérisson and Grandvaux Valleys, and even Mont Blanc on clear days.
Yes, parking is generally available at common starting points for trails around Lac d'Ilay, such as near La Chaux-du-Dombief or Le Frasnois. These spots provide convenient access to the various lake loops and other routes in the area.
The spring, summer, and early autumn months are ideal for running around Lac d'Ilay, offering pleasant temperatures and lush scenery. From April 15 to September 15, a voluntary tranquility zone is established to protect wildlife, ensuring a peaceful environment for your run. While winter running is possible, be prepared for colder conditions and potentially icy or snowy trails.
While the focus is on natural preservation, you can find cafes and small eateries in nearby villages such as La Chaux-du-Dombief or Le Frasnois, which are common starting points for many routes. These provide opportunities for refreshments before or after your run.
The running routes in Lac d'Ilay are highly rated by the komoot community, with an average score of 4.8 stars. Reviewers often praise the peaceful ambiance, the breathtaking turquoise waters, the backdrop of imposing cliffs, and the well-maintained network of paths that make each run a refreshing experience amidst stunning natural beauty.
Yes, for those who enjoy the sound and sight of waterfalls, the region offers routes that incorporate these natural wonders. The The Hérisson Waterfalls – Garnier Castle loop from La Chaux-du-Dombief is a challenging 4.1 km path that features varied terrain near the picturesque Hérisson waterfalls, providing a dynamic and scenic running experience.


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