In the center of the plaza there is a bronze statue of General José de San Martín, mounted on a horse and carrying a flag.
The statue is a copy of a monument erected in the French city of Boulogne-sur-Mer (the place of San Martín's voluntary exile and death), and was inaugurated on 21 May 1913.
The land where the plaza is located was donated by Marcos Paz in 1857, and was much larger than at present (extending several blocks to the south).
Its purpose was to serve as a marketplace, where cargo wagons that came and went between Rosario and other cities farther away from the littoral would stop to load and unload.
When the railway system was established, in 1871, the municipal government projected to build a square, which was referred to as Plaza San Martín already in 1884, while it was still an empty lot.