The ruins of Alt-Eberstein are the remains of the former Schloss Eberstein (Eberstein Castle), located on a hill near the town of Ebersteinburg and directly upstream of the modern city of Baden-Baden, in the state of Baden-Württemberg, Germany. The original structure was built in 1100 as the primary residence of the Counts of Eberstein, but by the end of the 16th century had been abandoned and much of the castle was torn down to provide materials for other structures. Presently it is a German national monument and a State Palace of Baden-Wuerttemberg.