The Palazzo Pretorio of Vogogna was built in 1348 at the wish of Giovanni Visconti, bishop of Novara, as the seat of the Vicar. It is located at the foot of the staircase that leads to the castle. Was the seat until 1819 of the government of Lower Ossola. Currently it is a multipurpose space, also used as a venue for conferences.
The building takes the architectural model of the Broletto lombardo and is supported by round arches resting on columns. The space covered under the porch was used for public meetings and as the market while the upper part housed the civil administration and judicial cooperation. Inside and outside are still partly visible fragments of ancient pictorial decoration including the Visconteo coat of arms at the top of the facade. It also houses in its interior the celtic Mascherone, soapstone, originally placed in the courtyard of the Church of San Pietro, where, at least from 1753, it was incorporated in a fountain decorated at the top with a fresco ("the Baptism of Jesus by St. John the Baptist"). The mask is a male figure that could represent a god Silvestre, Cernunnos, or a Celtic hero. The decorative elements are typical of the IV century B.C. even if some scholars, while connecting it to the world and to the Celtic culture the date back in time to the rear of the Roman conquest or even to the early middle ages. The adaptation of the mask in stone to the support tube of water spillage has profoundly altered the original expression of the face.