From the San Francisco Bay area, head East on Highway 4 past Pittsburg and Antioch. Go North across the Antioch Bridge (Highway 160). Follow Highway 160 North to Highway 12. Turn East onto Highway 12. Follow Highway 12 for approximately 3 miles. Turn Left at Jackson Slough Road and Right on Terminous Road, and go one mile South. Turn left on to Oxbow Marina Drive. Follow the road up onto levee and into the marina.
Coming North from San Francisco Bay, fork South at Pittsburg. Follow the San Joaquin River East to the entrance of the Mokelumne River, at the southeastern tip of Andrus Island. About 3 miles upstream, just after passing under the Highway 12 bridge, you'll find the entrance to Georgiana Slough to port. The waterway narrows here, but there's still plenty of water as you cruise a few more miles upriver to Oxbow Marina.
NOAA Chart Location: #18661 SC