Plaza Zaragoza is the historic heart of Hermosillo, flanked by the Cathedral of the Assumption, the Government Palace, and the old Town Hall. It is a properly working public square — shaded by large trees, busy during the day, and a gathering point for concerts and events on weekend evenings. The plaza has been refurbished over the years but retains its 19th-century layout and proportions.
The Government Palace on the north side of the plaza is worth a quick visit for the murals in its interior courtyard, which depict scenes from Sonoran history. These are well-executed if slightly official in their tone, but they give a useful overview of the region's past from the Yaqui wars through the Revolution.