The heart and main public space of the city. It has 17,000 m2 of surface, which transforms it into the wider the Coquimbo Region and one of the country's largest square. In 2007, renovation work is performed, which managed to give a more modern look, with a large central fountain, benches with engraved coat of the commune, and predominance of black and white. Its name is in honor of Montepío Márquez, Juan Nicolás de Agruirre and Barrenechea, Chilean politician and philanthropist, from the eighteenth century.