The classicist Wallenstein Palace (Valdštejský zámek) is the most dominant building of the southern side of the square. The original renaissance wing of the palace was built in the 17th century while then-owned by the Smiřický family.
An explosion, which damaged the castle in 1620, was the result of disagreements over Smiřický inheritance between sisters Eliška Kateřina and Markéta Saloména. A royal committee was taking inventory of the palace when gunpowder exploded in the vaults below. The explosion killed four workers and caused considerable damage to the castle. Under Albrecht von Wallenstein’s rule, the palace was repaired and other wings and buildings were added. Within the grounds, stables, a riding hall and an armoury were built. Architect Andrea Spezza oversaw the baroque reconstruction of the dilapidated building and preserved the impressive arcade courtyard.
Jičín palace came into the centre of affairs once more when Austrian emperor Francis I (also known as Francis II, Holy Roman Emperor) stayed at the palace in 1813. The Trauttmansdorffs, who sold the palace to the town of Jičín in the 1930s, were the last aristocratic owners of the palace. Before they left, however, the palace contents were moved to the Trauttmansdorff residence in Horšovský Týn.
You can see the interior of the castle by visiting the institutions the palace holds nowadays – the Regional Museum and Gallery or The World of Rumcajs Play Gallery. The Town Information Centre is also situated there, offering interesting tips for trips.
The palace park is an oasis of peace and quiet in the centre of town. Its current appearance is partly based on a design by depression-era architect Čeněk Musil. The extensive restoration of the park was finished in 2010. The lower part of the park has a pool with a fountain dominating the area. There is also a kiosk offering beverages and other refreshments. The upper terrace offers entertainment for children in form of a playground. Cultural events take place in the park; concerts and the summer cinema are especially popular.