Mark West Creek is a 29.9-mile-long (48.1 km)[2] stream that rises in the Mayacamas Mountains of Sonoma County, California, United States.

Discharge waters of Mark West Creek reach the Russian River after a confluence with the Laguna de Santa Rosa.

The Community Clean Water Institute has developed a program for monitoring pollutants in Mark West Creek.

The Creek passes Mayacama Golf Club and turns westward, emerging from hills east of the Sonoma County Airport.

It includes four cities (Santa Rosa, Rohnert Park, Sebastopol, and Cotati) and the incorporated town of Windsor.