The Estrella River is a 28.5-mile-long (45.9 km) tributary river in eastern San Luis Obispo County, California. The river forms at the confluence of , from the north, and San Juan Creek, from the south, near the town of Shandon. From there it flows west-northwest to its confluence with the Salinas River, of which it is a tributary, 8 miles (12.8 km) north of Paso Robles. Cholame Creek has its headwaters on the southwest side of and its tributary, Little Cholame Creek, begins on the northeast side. The creek drains the , which is bordered by Diablo Range on the east and Cholame Hills, a northern extension of the Temblor Range, on the west. The average precipitation in the area ranges from 11 to 17 inches (280 to 430 mm), increasing northward.