Château du Nideck, Medieval castle ruins in Oberhaslach, France.

Château du Nideck consists of ruins from two separate castles built in different eras within the Vosges forest. The upper fortress displays defensive walls, while the lower structure retains a square keep.

The upper castle was built around 1200; the lower castle with its 20-metre square keep followed after 1260. A 1264 charter names Burchard de Nidecke, and seals of burgrave Günther date to 1262. In 1454 Ludwig von Lichtenberg took Nideck as a robber-baron's nest, and the site was abandoned later in the 15th century.

The castle inspired a tale about giants collected by the Brothers Grimm in 1816, where a giant's daughter discovers farmers in the Alsace plains.

Visitors park at the Nideck Forest House and follow a clearly marked trail upward through the woods. The walk takes roughly 30 minutes with some steep sections, so wear appropriate footwear.

The 25-metre Nideck waterfall drops directly below the ruins, reached on foot from the Auberge Moosberg or the Nideck forest house on the D 218. The Brothers Grimm printed the giant legend in 1816; a Vosges Club plaque above the tower entrance commemorates Adelbert von Chamisso, who based his poem Das Riesenspielzeug on it.