| San Marino | |
| Source1 Location: | San Paolo Mountain |
| Mouth Coordinates: | 43.9632°N 12.3975°W |
| Subdivision Type1: | Country |
| Length: | 8.7km (05.4miles) |
| Source1 Elevation: | 864m (2,835feet) |
The San Marino is a river in the Italian peninsula. It flows through San Marino (Chiesanuova and Acquaviva), then north into Italy. For some of its length it forms part of the border between the two countries. It flows into the Marecchia at Torello, part of the commune of San Leo (Province of Rimini).