Discovery Bay is a census-designated place in eastern Contra Costa County, California in the United States, about 60 miles from San Francisco. It is located in the San Francisco Bay Area. As of 2020, its population was 15,358, a 15% percent gain from 13,352 at the 2010 census. Discovery Bay was originally a waterfront community built on a network of man-made dikes, surrounded by fresh water, except for the southeast quadrant, which comprises the golf course of Discovery Bay Country Club.