Marais du Syl Observatory – Observatoire le Rocher loop from Loire-Atlantique

Marais du Syl Observatory – Observatoire le Rocher loop from Loire-Atlantique

Hard

5.0

(2)

riders

Marais du Syl Observatory – Observatoire le Rocher loop from Loire-Atlantique

05:27

87.5km

490m

Gravel riding

Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels. The starting point of the route is accessible with public transport.

Last updated: September 10, 2026

Tips

Your route passes through a protected area

Please check local regulations for:

Parc naturel régional de Brière

Waypoints

Start point

Bus stop

Get Directions

33.2 km

Three old granite quarries, abandoned in 1980, which naturally filled with water to form beautiful blue ponds, popular with fishermen. Many of the cobblestones of Nantes and Nazaire streets come from this place.

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46.2 km

Lavau-sur-Loire

Highlight • Other

The old Saint-Martin du Sillon church has been listed as a historical monument since 1984.
Several beautiful old houses around this small town center.

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46.4 km

The Port House

Highlight • Cafe

This beautiful residence, which currently houses a crêperie, served as a model for the Maison dans la Loire, a work that can be seen in Couëron.
The small port in …

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51.6 km

Observatoire le Rocher

Highlight • Viewpoint

Wonderful landscape. to do from spring (flooded in winter)

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69.6 km

Cordemais Estuary Observatory

Highlight • Viewpoint

This observatory offers a clear view of the Cordemais channel, the Loire, the "Maison Cheminée" (Chimney House), and the magnificent coal-fired power station. A pleasant walk through the wetland area is also available. There are also picnic tables.

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70.2 km

Nice little port next to the racecourse

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The port of Cordemais is a blatant manifestation of the town's deep attachment to its estuary. Redeveloped in 2008, the site now offers more pitches and an ecological fairing area, …

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87.5 km

End point

Bus stop

Way Types & Surfaces

Way Types

49.3 km

31.7 km

3.23 km

2.68 km

722 m

< 100 m

Surfaces

33.2 km

28.1 km

22.3 km

3.92 km

131 m

Elevation

Nothing selected – click and drag below to see the stats for a specific part of the route.

Highest point (90 m)

Lowest point (0 m)

Weather

Tuesday 20 October

14°C

9°C

45 %

Additional weather tips

Max wind speed: 27.0 km/h

to get more detailed weather forecasts along your route

Comments

April 5, 2026,Randonnée Gravel organisée par " la Malvillenoise "😍

Excellent Gravel circuit organized by "la Malvillenoise" 👌
Too bad about the rain at the start, sometimes heavy 😕
With Thierry we ride hard and I like it a lot, unfortunately few people on the 90km Gravel ride and almost no overtaking 😏

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