Kasteln Castle, Medieval castle in Oberflachs, Switzerland

Kasteln Castle is the only uniformly Baroque palace in Aargau, built around a four-story medieval core with two-story wings added east and west between 1642 and 1650. It stands on a rocky outcrop west of Oberflachs, above vineyards and woods. The walls are largely of Mägenwiler Muschelkalk limestone, partly reused from the demolished Ruchenstein castle.

The fortress was built around 1200 in the Schenkenberger valley and first appeared in written records in 1238 as a property of Kyburg vassals. The Baroque renovation with its new wings followed in the 17th century, reflecting the owner's wealth and status.

The castle displays a unified Baroque design that took shape between 1642 and 1650, with four stories and two-story wings that transformed its appearance. This architectural makeover made it a distinctive landmark in the Aargau region during that period.

The property sits on elevated rocky terrain west of the village and is accessible via several pathways through the surrounding landscape. It now operates as a school with specialized facilities, so visitors should check in advance whether tours or visits are possible.

The 1642–50 wings were built partly from stone of Ruchenstein Castle, demolished in 1643 on the cliff directly behind Kasteln. The rest is mainly Mägenwiler Muschelkalk, a shell limestone. The castle's unusually rich interior was lost in the 1907 fire set by a pupil.