Breithorn, mountain summit in the Bernese Alps, Switzerland

The Breithorn is a 3,780 m peak in the Bernese Alps, on the border between the cantons of Bern and Valais. It stands roughly halfway between the Tschingelhorn and the Grosshorn, above the Lauterbrunnental and the Lötschental. Its north face drops 1,200 m of rock and ice into the Lauterbrunnental, and the glaciated Wetterlücke lies on the ridge toward the Tschingelhorn. The rock tower of the Kleines Breithorn (3,554 m) stands south of the main summit.

The Breithorn was first climbed on 31 July 1865 by the Bernese Alps pioneer Edmund von Fellenberg, accompanied by the guides Johann Bischoff, Peter Egger, Peter Inäbnit and Peter Michel from Lauterbrunnen and Grindelwald. The peak lies on the border between the cantons of Bern and Valais, between the Grosshorn and the Tschingelhorn.

The name Breithorn combines the German words for broad and horn, describing the wide rock-and-ice wall the mountain turns north toward the Lauterbrunnental. The summit ridge also carries the boundary between the cantons of Bern and Valais, so climbers cross a cantonal line on top.

The Breithorn is climbed from the Wetterlücke, the glaciated saddle between it and the Tschingelhorn, via the west ridge at grade III. There is no cable car or marked trail; parties need glacier travel and rock-climbing equipment. The summit lies on the Bern-Valais border, and the north face drops 1,200 m to the Lauterbrunnental.

The Breithorn is one of two mountains named Breithorn overlooking the Lötschental; the other is the Breithorn near Blatten. Its southern subpeak, the Kleines Breithorn, rises to 3,554 m as a rock tower below the main summit.