Burg Stein, Medieval castle ruin in Nassau, Rhineland-Palatinate, Germany

Burg Stein is a castle ruin in Nassau located between the Lahn valley and the Mühlbach stream. The remaining walls show a rectangular layout with a central tower, and visitors can still trace where the main residential building once stood.

The castle was the ancestral seat of the Reichsfreiherren vom und zum Stein, a family first documented in 1158; its most famous member was the Prussian reformer Heinrich Friedrich Karl vom und zum Stein. The building date is unknown, and the family held it as a fief of the Counts of Nassau, built as an outer fortification to protect the Nassau main castle. In the early phase of the Thirty Years' War the family moved its residence to the former tithe court in Nassau town, which they converted into the Steinsches Schloss; in 1636 the old castle was still reported in good condition. Towards the end of the Second World War its remains were largely destroyed.

The castle takes its name from the vom und zum Stein family, first documented in 1158 and held as a fief of the Counts of Nassau. Its best-known member, Heinrich Friedrich Karl vom und zum Stein, was a Prussian reformer. A local legend, the Frau von Stein, tells of a woman imprisoned in the castle by her jealous husband.

You can reach the site by walking up paths from the town of Nassau. The ruins are open to explore, though the ground is uneven and there are no facilities on site, so plan accordingly.

During the Thirty Years' War, the family abandoned the hilltop and moved into a converted tithe barn in the town below. That repurposed building became their new residence and still stands today.