Gutenburg, Medieval castle ruin near Aichen, Waldshut-Tiengen, Germany.

Gutenburg is a ruined hilltop castle in the Aichen district of Waldshut-Tiengen, set on a rocky granite knoll at the lower end of the deep Schlücht valley where the valley opens toward the Klettgau. Its first known structure was a tower built in the 10th century for the Abbey of St. Gallen; from 1128 a noble family raised a castle around it. The tower remained a St. Gallen fief even after the surrounding castle was treated as the family's own property.

In the 10th century St. Gallen Abbey built a tower on this granite spur to protect its lands between the Alb and Schlücht. In 1128 the abbey granted the tower as a fief to an unnamed noble family, who built a castle around it. In 1187 the castle passed to the lords of Gutenburg, from whom it took its name. In 1525 insurgents under Hans Müller briefly occupied it.

The name Gutenburg probably comes from the von Gutenburg family, a free ministerial lineage from the Swiss Aargau, and was adopted around 1187. The 13th-century minnesinger Ulrich von Gutenburg may be the same Ulrich von Gutenburg who appears repeatedly in charters. In 1525, insurgents under Hans Müller briefly occupied the castle with support from the city of Waldshut.

The ruin sits at the lower end of the narrow Schlücht gorge, where the valley opens toward the Klettgau; the approach follows the stream cut into Black Forest granite. The site is a ruin without visitor facilities, so wear sturdy shoes for uneven ground. The nearby town of Waldshut-Tiengen provides the closest services.

The castle's name probably came from the lords of Gutenburg, a free noble family from the Aargau, and only after 1187; the minnesinger Ulrich von Gutenburg, active in the 13th century, may be the same Ulrich who appears repeatedly in charters. In 1525 rebels under Hans Müller briefly seized the castle with Waldshut's support before being defeated and forced to pay damages.