Trosky Castle (Czech: Hrad Trosky) is a castle ruin located some 10 km south of Semily, Liberec Region, Czech Republic. It is one of the most famous Czech castles and is situated on the summits of two basalt volcanic plugs. On the lower peak (47 m) is the two-storey structure called Baba (Old Woman), and on the higher outcrop (57 m) is the four-sided structure known as Panna (Virgin).