The 10-km-long walk from Sonvilier to the Hôtel Chasseral leads past the castle ruins of the former Erguël castle, along Jura moors and the upper part of the "Combe Grède".

The Combe-Grède, a spectacular chasm in the Jurrassic limestone, literally divides the mountain vertically into two parts. The walk takes 3.5 hours. You can reach Sonvilier by train; a bus service operates from the Chasseral.