Mont Châteleu, Mountain summit in Doubs department, France

Mont Châteleu is a summit in the Jura reaching 1,302 metres on a southwest–northeast crest. The ridge lies on the watershed between the Mediterranean and the North Sea, and the French–Swiss border runs along its southeastern slope. Its dark forested flanks are broken by snowfields, including a broad open snowfield descending diagonally on the right.

Mont Châteleu lies on a southwest–northeast crest line of the Jura. The summit, at 1,302 metres, stands on the territory of Grand'Combe-Châteleu; its northwest slope falls in the French commune of Les Gras, its southeast slope in the Swiss commune of La Brévine. The Franco-Swiss border runs along that southeast slope, and the ridge sits on the watershed between the Mediterranean and the North Sea.

The mountain acts as a natural boundary between two drainage basins that has shaped how communities settled and organized themselves across generations. You can see this influence reflected in where villages and paths are located relative to the ridge.

Hiking trails reach the summit from the French commune of Les Gras to the northwest or the Swiss village of La Brévine to the southeast. Both routes require sturdy footwear and proper preparation since mountain weather can change rapidly at elevation.

The summit sits exactly on the watershed dividing the Mediterranean and North Sea basins, and the French-Swiss border runs along its southeastern slope. The commune of Grand'Combe-Châteleu lies on the French side, while La Brévine in Switzerland faces it across the ridge.