Discovery Bay, CA has a population of 14,765 and is the 2,875th largest city in the United States. The population density is 3,911 per sq mi which is 1428% higher than the California average and 4217% higher than the national average. The median age in Discovery Bay is 41 which is approximately 14% higher than the California average of 36. In Discovery Bay, 64% of the population over 15 years of age are married, 90% speak English and 5% speak Spanish. 68% of Discovery Bay residents were born in California, 23% were born out of state, 1% were born outside of the United States and 8% were foreign born.