The most preserved part of the castle - the cylindrical tower with a gallery. It has been a dominant feature of the Náchod area since the beginning. Its function is obvious - it is the main defensive element of the castle complex. The tower was originally accessible only from the second floor, but during the Renaissance reconstructions it gained an entrance from the courtyard. During the Renaissance the tower was provided with an arched gallery (it was modified under Ottavio I Piccolomini). Both the gallery and the loopholes located directly from the gallery were used for defence. Over the centuries, the use of the tower expanded. The rooms in the tower were used to store weapons as well as food. It was also an important communication element between the castle buildings, which was used by the servants. Interestingly, there is a hunger room in the middle of the tower.

The entire south side of the main building has a Renaissance terrace with a magnificent view of the city. In its centre, a Renaissance loggietta dominates.

Gothic cellars with a sample of the foundations of the original castle from the thirteenth century. In the cellar you can also see a well.

The extensive castle library is located in the castle premises, which are not yet open to the public. The Náchod library has been shaped since the Piccolomini. In the second half of the 19th century, when the estate was owned by William of Schaumburg-Lippe, the library in Náchod was united with the library in Ratibořice, which had been located in Náchod since then. Arnold Weihe-Eimke and Otto Elster were employed to manage the library and the archives at Náchod Castle, and in addition to managing the extensive collections, they also worked on the history of Náchod. While the archival materials were transferred to the archives in Zámrsk after 1945, the library is still in place and contains around 26,000 volumes. In addition to books, there are many periodicals, records and maps.