The first section of the GR5 in Switzerland. The route takes you from the ferry terminal in Nyon up the the train station in la Cure. Beginning with a flat section before it reaches the Jura mountains, then ascending for a period, before flattening out after St-Cerge. The finish is at the train station in la Cure which means an easy 50 minute train back to Nyon.
The Nyon to St-Cergue section is described below
"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.
The Roman Road crosses several places the road, please pay attention during peak hours!"
https://www.lacote-tourisme.ch/en/V767/st-cergue-to-nyon
