Dorneck Castle, Medieval castle ruin in Dornach, Switzerland

Dorneck Castle is a ruined medieval fortification in Dornach, Solothurn Canton, situated on elevated terrain that overlooks the surrounding area. The remaining stone walls and tower fragments display construction techniques from different periods of the Middle Ages.

The castle was first documented in the mid-14th century, but finds show it existed from about the mid-11th century, founded by the lords of Pfeffingen. It passed to the counts of Saugern and around 1200 to the counts of Thierstein, who sold it in 1360 to Duke Rudolf IV of Habsburg and held it back as a fief. Solothurn bought it in 1485.

The name Dorneck comes from the rock spur above Dornach, and the site is a Swiss heritage site of national significance. Visitors reach the inner gate past stone cannonballs found in the rubble of the fortress, and the Schlosshof, the estate that grew with the castle, now serves as a restaurant.

The ruin is reached from Dornach village by following Schlossweg, a walking path that climbs from the lower area up to the site. The grounds and remaining structures are open to visitors, though the terrain is uneven and some parts have loose stones or open drops.

The large bastion on the highest rock spur is solid masonry with no interior rooms; it was built to carry heavy artillery. Stone cannonballs found in the rubble now decorate the inner gate. An iron staircase from the central courtyard leads up to the bastion.