Tres Ríos is a district of the La Unión canton, in the Cartago province of Costa Rica. Its name is derived from its location at the confluence of the Tiribí, Chiquito and Cruz rivers.

Interurbano Line, is a commuter railway line in Costa Rica, operated by the national public railway operator Incofer. The line connects the provinces of Alajuela, Heredia, San José and Cartago.