Schloss Weilburg is a Baroque schloss in Weilburg, Hesse, Germany. It is located on a spur above the river Lahn and occupies about half of the area of the Old Town of Weilburg. It contains the Hochschloss, built between 1530 and 1572, which is one of the best-preserved Renaissance palaces in Hesse. In the 1700s, the palace was expanded by John Ernst, Count of Nassau-Weilburg, and his builder, Julius Ludwig Rothweil. The buildings and gardens now belong to the Verwaltung der Staatlichen Schlösser und Gärten Hessen, and they can be visited as a museum on guided tours. Parts of the palace are venues for the music festival Weilburger Schlosskonzerte, which is named after the palace.