High Quality Content by WIKIPEDIA articles! The Russian River springs from the Laughlin Range about 5 mi (8 km) east of Willits in Mendocino County. It flows generally southward to Redwood Valley, then parallels U.S. Route 101 past Calpella, to join the East Fork Russian River just below Lake Mendocino. From there the Russian River flows south, past Ukiah and Hopland, and crosses into Sonoma County just north of Cloverdale. Closely paralleled by U.S. Route 101, it descends into the Alexander Valley, where it is joined by Big Sulphur Creek. It flows south past Cloverdale, Asti, and Geyserville.