They form the natural boundary between the canton's Toggenburg and Sarganserland districts.

They consist of a limestone ridge running east to west, with the individual peaks formed by erosion.

The ridge is defined much more sharply to the south than to the north, with an almost vertical drop of several hundred meters towards Walenstadtberg and eventually Lake Walensee at 419 m. The southern slope of the range was significantly formed by the Rhine Glacier during the Würm glaciation.

The name is a plural, indicating the peaks forming the historical boundary of the bishopric of Chur.

It has historically also been folk-etymologized as Kurfürsten, i.e. the 7 prince-electors of the Holy Roman Empire who in the later medieval period (until 1648) numbered seven, which in turn encouraged the count of seven main or "official" peaks.