Largest ancient castle, once owned by Rozmberk and the Schwarzenbergs, currently includes a two-storey Palace with four wings, and a high tower. Its Northern gates open onto the Masaryk square. Through them and get many visitors to the territory of the Třeboň castle. Currently the castle houses the city archives, which is based on the most valuable records of the Rosenberg. Also in the castle is a local history exhibition, which is called "the House of nature třeboň". Finally, after a renovation in 2005 was opened to the public Schwarzenberg hall, which now hosts concerts and various important events.

The třeboň Chateau was built by Reimburseme in the second half of the XIV century on the site of the estate, which arrived simultaneously with the Foundation of the city. The castle was greatly enlarged in 1479, when it became the main residence of the local lords. However, the fire that broke out in 1562, prevented them to enjoy their Gothic castle. What remained of the fortress, had to rebuild. The new building of the Palace was built in Renaissance style and surrounded by luxury English Park.

In the beginning of XVII century the castle was connected with the neighbouring Augustinian monastery covered walkway, which was called "Long". Due to several houses in the square, the Palace was expanded. He acquired the art gallery and library.

In 1660 Trebon Palace acquired the representatives of the noble Schwarzenberg family. This castle has become the first Czech property, so they paid him great attention. On the site of the former castle brewery was built as a Baroque mansion, where he settled managing the possessions of the house of Schwarzenberg. In 1712, during the accomplishment of the castle-site of the courtyard of the Palace was decorated with a fountain. Water dripped from their mouths Turkish soldiers. Sculptural composition also included a Raven, who mercilessly pecking at the enemy. The fountain can still be seen.

After the Second world war, the castle was nationalized.