The Munger fort building occupies as one of the finest sites inside the fort and has now been converted into a Jail. Though locally known as the palace of the Mughal Prince Shuja. It is inferred to have been built earlier by Nawab Mir Qasim Ali, who also ruled from Munger.
The building is enclosed by a high wall on three sides and by the river on the fourth or west side. It consists mainly of a Khas Mahal or Zenana Palace (now used as “the under trial ward”), the Diwane-I-Am or Public Audience Hall (now used as a school for prisoners), and the Top-Khana or Armory with 10′ – 15′ thick walls (now used as the dormitory).
There was also once a small mosque on the west side of the palace, now in ruins, but used as ration godowns.
An interesting feature noted below the floor of the mosque is a dry well or pit of 10–12 feet (3.0–3.7 m) depth, which leads to several underground tunnels running in different directions.
The well was, in earlier times, connected to the river through an opening, which has since been shored up.