Filialkirche, Chapel in Klausstein, Ahorntal, Germany.

The Klausstein Chapel stands on a limestone rock at 435 metres, 60 metres above the Ailsbach valley near Klausstein in the Franconian Switzerland. It consists of a small rectangular nave with a Romanesque core and a three-sided late Gothic choir (around 1450) to the east, built of rubble stone. The Romanesque round-arched windows are walled up, and a roof turret in the west holds a small silver bell.

The chapel is the remnant of a castle probably built in the 11th century by the Lords of Ahorn and first mentioned in 1139; Romanesque round-arch windows in its walls date from this period. When the family died out in 1272, the Lords of Rabenstein took over the chapel, and from 1390 it was no longer a castle chapel but an independent place of worship. In 1566, under the Rabensteins, the Catholic St. Nicholas Chapel became Evangelical Lutheran and is now a branch church of Kirchahorn.

The chapel's name derives from the Klausstein, the limestone rock on which it stands, not from a hermit. As a former castle chapel of the Lords of Ahorn, it kept its own patronal right; since 1390 it has counted as an independent sacred building, and since 1566 it has been Evangelical Lutheran, today a branch church of Kirchahorn.

The path up to the chapel is steep and requires sturdy footwear and careful footing. Visit during good weather, as the rocky approach can be slippery after rain.

A silver bell hangs in the western tower turret, operated by a rope system from the gallery. This hand-rung chiming system is a rare example of how isolated locations once communicated through bell signals.