By using the ancient Roman roads, it is possible to connect St-Cergue to Nyon via Trélex. This path is also part of the GR5 hike trail.
At the beginning of our era, two roads, one from Nyon and the other from Aubonne, met at Saint-Cergue to penetrate into Gaul.
These roads had to be frequented not only by soldiers from Rome, but also by the populations of Savoy and the Pays de Vaud, who were getting supplies of salt in Grozon, Salins and Lons-le-Saunier.
Today this road is used by the GR5 hike trail which connects the North Sea to the Mediterranean.
Length: 12 km