Dubno Castle was built by Prince Yanush Ostrozkyi in the middle of the 17th century in the style of the late renaissance on the basis of the previously built fortifications in 1492, the castle is considered to be one of the oldest castles in Ukraine with an extensive system of underground passages, which hid the locals during the attacks of foreigners.
The location of this castle, which is a bastion type fortification, is advantageous in the strategic plan, as it is protected by the River Ikva and the marshy wetlands. Two powerful bastions with casemates are located on the side of the city and separated from it by a deep moat. On the corners of the bastions are small cavalier turrets, such as Beatka Tower or the Maiden Tower. The entrance to the castle was ensured through the bridge and gates arranged in the Overgateway corpus.
Dubno Castle Complex consists of three architectural monuments: Over-gateway corpus of the 17th century, of the Ostroh Princes' Palace, Lubomirski Palace late 18th century.
It was based on the entrance gate building, constructed in the 17th century with the Renaissance portal. The gates are the emblem of the Princes of Ostroh which is in a beautiful frame. The first floor was used to house servants and guards, the second floor housed the owner's living rooms and the cellars were used as a castle arsenal.
In the castle courtyard, to the right of the gate, the palace of the Ostroh princes was constructed as a one-story service outbuilding called an outhouse in the 17th-18th centuries. Here the castle administration - housekeeper, treasurer and governor was located. In the 18th century the second floor of the palace was completed. It is here that the archives of the castle owners, the surrounding nobility of the Princes of Zamoyski, Koniecpolski, Zbaraski, and Chartoryski were stored.
The palace decoration is an oriental geometric ornament, which is located around the perimeter and divides the first and second floors of the building. Underneath the palace, there are deep and spacious dungeons that are now used for exposure of "The History of Torture and Punishment.
The palace of the princes of Lubomirski is a separate monument of architecture in the castle complex. It was built on the old foundation in the 80s of the 18th century at the expense of the castle owner, Polish Prince Mykhailo Liubomyrskyi. The palace was built by the chief architect of the Commonwealth, the famous Italian architect Domenico Merlin in the Western European style of classicism.