Chäserrugg, Mountain summit in Toggenburg, Switzerland

Chäserrugg is the easternmost summit of the Churfirsten range in canton St. Gallen, Switzerland, standing at 2,262 meters (7,421 ft) above sea level. The peak is made of layered limestone and looks out over the Toggenburg valley, Lake Walenstadt, and on clear days a broad arc of Alpine peaks.

The name refers to the cheesemakers who once used this high pasture for herding and dairy work, and the word for ridge in the local dialect. The Churfirsten group, of which this is the easternmost peak, was formally defined in the early 20th century as a set of seven summits.

The summit restaurant, designed by Herzog & de Meuron, replaced the earlier summit restaurant in 2015 and won the Hase architecture prize in bronze that same year. The name Chäserrugg means "cheesemaker's ridge", originally the name of the ridge rising from Ruggschöpf at about 1,800 m. In the 19th century the Churfirsten were sometimes etymologized as Kurfürsten, giving the variant Kaiserruck.

The summit is reached in two stages, first by funicular from Unterwasser to Iltios, then by a gondola to the top area. Weather can shift quickly at this height, so carrying an extra layer and checking the forecast before departure is a good habit.

The summit restaurant was replaced in 2015 by a new building designed by Herzog & de Meuron, which received the Hase architecture prize in bronze that same year. The old lift from Iltios to Stöfeli was also replaced in summer 2015 by a 10-seat gondola line running Espel–Stöfeli–Chäserrugg.