| San Martin | |
| Native Name: | Departamento San Martín |
| Settlement Type: | Department |
| Coordinates: | -28.25°N -120°W |
| Subdivision Type: | Country |
| Subdivision Name: | Argentina |
| Established Title: | Established |
| Seat Type: | Seat |
| Seat: | Brea Pozo |
| Leader Title: | Mayor |
| Unit Pref: | Metric |
| Area Total Km2: | 2097 |
| Population Total: | 9854[1] |
| Population Density Km2: | auto |
| Postal Code Type: | Postal Code |
| Area Code Type: | Area Code |
San Martín is a department of Santiago del Estero Province (Argentina), and one of the twenty-seven administrative units of the province.