Třeboň is a spa town in Jindřichův Hradec District in the South Bohemian Region of the Czech Republic. It has about 8,300 inhabitants. The hi…Třeboň is a spa town in Jindřichův Hradec District in the South Bohemian Region of the Czech Republic. It has about 8,300 inhabitants. The historic town centre with the castle complex is well preserved and is protected by law as an urban monument reservation.