The large castle complex, once belonged to Rosenberg and Schwarzenberg, currently includes two-storey palace, consisting of four wings, and a high tower. Its north gate located on Masaryk Square. Through these and many visitors come to the territory of Třeboň castle. Currently, the castle houses the city archives, which is based on the most valuable records Rosenbergs. Also in the castle is a local history exhibition, which is called the "House of Nature Trebon." Finally, after reconstruction in 2005 it was open to the general public Schwarzenberg hall, which now hosts concerts and various important city events.

Castle Trebon Rosenberg was built in the second half of the XIV century on the site of the lord of the estate, which appeared here simultaneously with the foundation of the city. The castle was significantly expanded in 1479 when it became the main residence of the local lords. However, a fire broke out in 1562, prevented them from enjoying their gothic castle. What remains of the fortress, had to rebuild. The new building of the palace was built in the Renaissance style and surrounded by his splendid English park.

At the beginning of XVII century the castle was connected to the neighboring Augustinian monastery covered passage, called "long". Due to a few houses, located on the square, the palace extended. He bought an art gallery and a library.

In 1660 the palace was acquired by representatives of Trebon Schwarzenberg noble family. This castle was the first Czech of their property, so they paid him much attention. On the site of a former castle brewery was built a baroque mansion, where he settled managing the Schwarzenberg estates. In 1712, during the accomplishment of the territory of the castle courtyard of the palace was decorated with a fountain. Water dripped from their mouths Turkish soldiers. The sculpture also included raven pecked mercilessly enemy. The fountain can be seen now.

After World War II the castle was nationalized.