Burg Werdenstein, Medieval castle ruins in Immenstadt, Germany

Burg Werdenstein is a ruined hilltop castle on a sandstone hill above the Illertal valley in Immenstadt, Bavaria. Only the gate tower, about six metres high and built of sandstone and rubble, and a few foundation traces remain; the tower has four west-facing gun slits for handguns, horizontal outside and vertical inside. A small chapel was reconsecrated on the site of the medieval castle chapel beneath the former keep.

Hildebrand von Werdenstein appears as a witness in a 1239 Kempten Abbey charter, the family's first recorded member. From 1350 the Werdensteins served the abbey as hereditary chamberlains; around 1400 they submitted to the House of Austria. In 1525 rebels plundered the castle during the Peasants' War, and lord Georg fled to Kempten and wrote the Werdensteiner Chronik. The family sold the castle in 1785 to the Counts of Königsegg-Rothenfels.

The gate bears a memorial plaque from 1929 listing dates in the castle's history; such plaques were installed across Allgäu ruins on the initiative of Kempten mayor Otto Merkt. The plaque's dates are not always historically accurate. The site now serves as a beer garden for the adjoining Burg-Café, run by the Rapp family, who bought the land in 1898.

The ruin is fenced and inaccessible; the gate tower and wall remnants can only be viewed from outside. The beer garden of Burg-Café occupies the former economic yard in front of the castle, and the farm is still run by the Rapp family. The modern access runs along the castle hill, not over the original bridge.

The gate tower's two storeys hold four gun ports on the west side, built for hook guns: on the field side they appear as horizontal slits, but inside they run vertically. Small square openings set at a slant pierce the side walls. A 1929 memorial plaque above the arch mixes dates, and not all of its details are historically accurate.