Chäserrugg is a mountain in Wildhaus-Alt St. Johann municipality, Toggenburg, canton of St. Gallen, Switzerland, rising to 2,262 m. It is the easternmost of the "seven peaks" of the Churfirsten, the other six being, running east to west, Hinterrugg, Schibenstoll, Zuestoll, Brisi, Frümsel, Selun. In spite of its being counted among the "seven peaks", it has a modest prominence of just 14 m, forming part of the ridge ascending to Hinterrugg.