The Salinas river is 155 miles long. The river is fed by the major tributaries the Namcimento and San Antonio Rivers in the southern end of the Salinas Valley. The Salinas River is the primary water source for the Salinas valley farms and vineyards. In Monterey County the Salinas river is fed by the Arroyo Seco River. The Salinas River is a shallow river with most of its water flow running underground. The river is the longest underground river in America. The Salinas River National Refuge is great spot for birding, located adjacent to the Salinas River State Beach near Moss Landing. The Salinas river does not run directly into Monterey Bay. The Salinas River is diverted into the OLD Salinas River that flows into the Monterey Bay.

The Salinas river does not run directly into the Monterey bay instead the river feeds this large lagoon.