Laufenburg ruin, Medieval castle ruin in Laufenburg, Switzerland.

Laufenburg ruin is a castle structure on a rocky hill south of the old town, with its stone keep rising high above the Rhine River. The preserved tower with its open observation deck allows views across the river to both sides of this border town.

Around 1180 the Habsburgs acquired the area and built fortifications on both banks of the Rhine. Rudolf III moved his residence into the southern castle, rebuilt it as a residence and founded the Habsburg-Laufenburg line; the keep visible today dates from this period. In 1386 Count Hans IV sold the castle and lordship to Duke Leopold III of Austria for 12,000 guilders. Troops from Basel and Bern damaged it heavily in 1443 during the Old Zurich War, and in 1787 it was cleared and used as a stone quarry.

The name Laufenburg refers to the castle and the settlement that grew around it; the town received its charter in the 13th century, renewed in 1328. The Habsburg-Laufenburg line, founded by Rudolf III, took its name from this residence. Visitors today see the keep and ring wall that shaped the small town on the south bank of the Rhine.

The ruin is easily reached from the town center and the path up is well marked and manageable. The tower is open to visitors, and the observation terrace gives special views over the surrounding area and both sides of the divided town.

The keep's viewing platform stands 13 metres up and is reached by 72 steps. From it you can see the two halves of Laufenburg on either bank of the Rhine, the Swiss town in Aargau and the German town in Baden. The keep itself was built in the 13th century, when Rudolf III turned the southern castle into a residence.