The external view of the castle "Katz" clearly illustrates the ongoing conflict between the Kurtrier and the Counts of Katzenelnbogen, just like its counterpart, the castle "Maus".
The name "Katz" was given to the castle in St. Goarshausen by popular opinion, which actually originated as Burg Neu-Katzenelnbogen in 1371. With it, the Counts of Katzenelnbogen aimed to protect their possessions along the Rhine, particularly the customs office in the opposing St. Goar - as well as deliberately establishing a counterbalance to the Kurtrier castle "Maus", which threatened their customs processing. Like many Rhine castles, it ultimately could not withstand the French troops, and the castle was destroyed in 1806. It took almost a century before a historicized reconstruction from 1898 to 1899 transformed the ruins into a magnificent residence.

The castle is privately owned and can only be viewed from the outside.