Blackenstock, Mountain summit in Uri, Switzerland

Blackenstock is a mountain summit in the Uri Alps reaching approximately 2,930 meters (9,610 feet) in height. The peak sits within a ridge system and stands between the towns of Altdorf and Engelberg in the Swiss Alps.

Blackenstock, at 2,930 m, lies on the territory of Attinghausen and Isenthal in the canton of Uri, just northwest of the Surenen Pass. With the Engelberger Rotstock, Wissigstock and Brunnistock it closes off the Isental valley. The Surenen Pass below it has long been the crossing between the Isental and the Engelberg valley.

The name Blackenstock follows the local pattern of naming peaks after the alps below them; the Blackenalp lies on the slopes above Attinghausen. The summit closes the Isental valley together with the Engelberger Rotstock, Wissigstock and Brunnistock, and the Surenen Pass path below has long carried herders and travellers between the Engelberg and Uri valleys.

No marked trail leads to the summit; the usual approach is a high-alpine route from the Isental via the Gitschenhörelihütte, reaching the top by the west ridge (ZS) or the east ridge (WS+). Both routes cross the Blüemlisalpfirn in their lower section, so glacier equipment and experience are needed. The terrain drops abruptly several hundred metres toward the Surenen Pass.

No marked trail leads to the top; climbers reach it as a high tour from the Isental via the Gitschenhörelihütte, gaining the summit by the west ridge (ZS) or the east ridge (WS+), both crossing the Blüemlisalpfirn in their lower section.