The Dammastock (3,630 m) is the highest mountain in the Urner Alps in Switzerland. Its summit ridge forms the border between the cantons of Uri and the Valais. It is the highest summit in the canton of Uri. The tripoint between the cantons of Berne, Valais and Uri lies near the Eggstock, north of the Dammastock. Politically, the Dammastcok is split between the mnunicipalities of Göschenen (Uri) and Obergoms (Valais).
The massif is almost completely covered by ice, the large Rhone Glacier on the west side, the smaller Damma Glacier on the east side and the Trift Glacier further on the north side. It was first climbed by Albert Hoffmann-Burkhardt with guides Johann Fischer and Andreas von Weissenfluh on 28 July 1864.