Palazzo del Duca faces right in front of the Rocca Roveresca. Commissioned by Guidubaldo II della Rovere in the mid-sixteenth century on a project by Gerolamo Genga, it was enlarged in the decades immediately following by his son and heir Francesco Maria II, the last representative of the dynasty, who altered the symmetry of the facade, making the entrance portal is then placed on the left. The palace was not designed to house the duke permanently, but rather as a representative residence for the court and for its illustrious guests, who could admire the military parades that took place in the square from the windows.

Inside, a splendid coffered ceiling attributed to Taddeo Zuccari embellishes the Throne Room. The forty-nine coffers were most likely made between 1553 and 1555 and recall joyful, cheerful, festive atmospheres. But we can also see irony and satire towards political and cultural power: the master Zuccari paints carnival themes showing an imaginary world upside down, where children, represented by putti, rule over adults, and the poor over the rich. Also in the Throne Room is also visible a genealogical tree on paper of the Della Rovere family.

The building overlooks the square of the same name, whose name refers instead to Giovanni Della Rovere. The square has unique characteristics for the Renaissance period: no religious building overlooks it and the so-called Fountain of the Anatre (or the Lions) is located in a decentralized position, thus confirming the military use of this space.