The Carmelite convent, together with the adjoining Church of the Annunziata, had been founded in 1371 by Guglielmo Peralta, then Lord of Caltanissetta, and had always been the venue for popular assemblies, convened by the sound of the bell placed on a tower right next to the convent.
The location of the convent and the Church of the Annunziata on the main square, as well as their ancient tradition as a place for civic decision-making, were decisive in the choice to establish the new town hall there following the unification of Italy. This required the demolition of the Church of San Paolino and the adjacent bell tower, as well as a major transformation of the layout of the Carmelite church and convent.
The main façade, located at the corner between Piazza Garibaldi and Corso Umberto I, is in Neoclassical style and has two levels. The main entrance leads to an inner courtyard with a portico, where concerts and cultural events are periodically held.