Strahlenfelser Schlossberg, Medieval castle ruins in Simmelsdorf, Germany.

Strahlenfelser Schlossberg is a wooded rocky hill in Simmelsdorf, rising to 587 meters, with the site of the vanished Strahlenfels castle on a western rock spur at 570 meters. Only low, irregular fragments of grey stone masonry remain among the trees and grass, and the castle rock now serves as a climbing rock and viewpoint.

The castle first appears in a 1254 document naming Heinricus de Stralenvels as a witness, and was probably built shortly before. Around 1310 the Strahlenfels family moved to their new water castle at Reichenschwand and ceded the site to the Wildenstein family. In 1360 Heinrich V. von Wildenstein sold the castle to Emperor Charles IV for 1900 pounds of heller; it was later pledged and passed back to the Wildensteins in 1426. After 1547 building damage went unrepaired, and by 1589 it was barely habitable.

The name Schlossberg refers to the castle that once dominated this hilltop and shaped the local landscape. Today the site draws visitors interested in exploring medieval structures and enjoying views across the region.

Reaching the ruins requires good footing and physical effort as the path crosses uneven ground. Sturdy footwear and time to explore are necessary, since there are no accessible routes or comfortable approaches to the site.

The castle rock itself, not the ruins, is what climbers come for: the crag above Strahlenfels is used as a climbing rock and viewpoint. From the site, the neighbouring Wildenfels ruin is visible to the northwest, built by the Wildenstein lords in sight of Strahlenfels around the late 13th century.