Gräfenstein Castle (German: Burg Gräfenstein) is a ruined rock castle about 2 kilometres (1.2 mi) east of the village of Merzalben in the German state of Rhineland-Palatinate. It is in the county of Südwestpfalz within the Palatine Forest and is often called Merzalber Schloss ("Merzalben Castle"). It is built on a rock plateau 12 metres (39 ft) high at an elevation of 447 metres (1,467 ft) above sea level.