Felsenburg, Castle ruin in Kandergrund, Switzerland

Felsenburg is a ruined hill castle at 1060 m above sea level above the municipality of Kandergrund in the canton of Bern. Only the rectangular main tower and remnants of the outer walls remain standing on the rocky spur. The site lies near the Tellenburg and the Mülenen castle ruin.

Felsenburg was probably built in the 12th century for the Freiherr of Kien and controlled the road over the Gemmi pass. It passed to the Freiherr of Wädenswil in 1290 and to the Freiherr of Turn in 1312. Recorded in 1339 as castrum de Petra and in 1368 as Stein, it was acquired by Bern in 1400 and left to fall into ruin.

The castle's name shifted with its documentation: it appears as castrum de Petra in 1339 and as Stein in 1368, both meaning stone, a reference to the rocky spire it occupies. It is listed as a Class A Swiss cultural property of national significance. The rectangular keep and outer wall remnants are what remain for visitors to see.

The ruins sit on a rocky hilltop requiring a short walk from the valley. The ground is steep and uneven with exposed rocks, so sturdy footwear and careful footing are needed.

The castle appears in records under two names: castrum de Petra in 1339 and Stein (German for stone) in 1368, both referring to its rocky spur above the Gemmi pass road. The rectangular main tower and remnants of the outer walls are all that remain standing.