Lake Solano is a small reservoir on Putah Creek in the Vaca Mountains of northern Solano and Yolo counties, California. Formed by Putah Diversion Dam about 6 miles below Monticello Dam, it stores water that is diverted into the Putah South Canal for agricultural and urban use, giving it both practical and scenic importance. About 1.5 miles long and holding 750 acre-feet, it also anchors Lake Solano County Park, where visitors picnic, camp, paddle, boat, swim, fish, watch birds, and hike. Fish caught here and in Putah Creek are subject to a safe-eating advisory because of elevated mercury levels.