Katz Castle (German: Burg Katz) is a castle above the German town of Sankt Goarshausen in Rhineland-Palatinate. The castle stands on a ledge looking downstream from the riverside at Sankt Goar. It was first built around 1371 by Count William II of Katzenelnbogen. The castle was bombarded in 1806 by Napoleon and rebuilt in the late 19th century, in 1896–98. It is now privately owned, and not open for visitors.