Situated at the northern end of pedestrianized Florida Street, the park is bounded by Libertador Ave. (N), Maipú St. (W), Santa Fe Avenue (S), and Leandro Alem Av.
The Revolution of 1810 brought an autonomous government to Buenos Aires, which entrusted the Mounted Grenadiers to José de San Martín and allowed him to establish his main barracks at the plaza.
Following his decisive military victories, Gen. San Martín was forced into exile in 1824 for political reasons; but a reappraisal of his place in history led to his becoming nearly eponymous in Argentina after his death in 1850.
Accordingly, French sculptor Louis-Joseph Daumas was commissioned in 1862 to create an equestrian statue of the hero of the Wars for Independence and the square was renamed in his honor in 1878, upon the hundredth anniversary of his birth.
Its western section was separated to make way for a rerouting of Maipú Street in 1972; but President Néstor Kirchner ordered the change reverted in 2004, in response to long-standing appeals by neighbours and friends of the park.