Rötteln Castle (German: Burg Rötteln), located above the Lörrach suburb of Haagen, lies in the extreme southwest corner of the German state of Baden-Württemberg, just 10 kilometres (6 miles) north-east of the Swiss City of Basel . The fortification was one of the most powerful in the southwest, and today, it is the third largest castle ruin in Baden.

The castle remains are located on a prominent wooded hill 422 metres (1,385 feet) above sea level. The keep lies on a spur projecting from the steep-sided east side of the lower Wiese valley.

The castle has probably existed since the beginning of the 11th century. The first documented mention of a lord of Rötteln, one Dietrich von Rötteln, the bailiff of St.