Take Interstate 80 to the Elm Avenue exit in Auburn. Edit to the south of Interstate 80 onto Elm Avenue and continue on Elm Avenue to Highway 49 in Auburn (less than ? mile). Stay on Highway 49 to Coloma, pass James Marshall State Park, and continue straight onto Coloma Heights Road. (Highway 49 makes a sharp right hand turn but you'll go straight) and bear left on New River Road to the American River Campground. (Driving time approximately 2 hrs.)