San Luis is a province of Argentina located near the geographical center of the country (on the 32° South parallel). Neighboring provinces are, from the north clockwise, La Rioja, Córdoba, La Pampa, Mendoza and San Juan.
The main rivers of the provinces are the Conlara and Quinto, and the border rivers of Desaguadero River and Salado River.
It was the only province in Argentina which does not change the hour during summer, remaining at UTC-3 while the rest of the country changes to UTC-2. However, in 2008 most Andean and Western Argentinean provinces have joined San Luis and remained at UTC-3.