Antioch, CA has a population of 108,675 and is the 272nd largest city in the United States. The population density is 3,703 per sq mi which is 1494% higher than the California average and 3987% higher than the national average. The median age in Antioch is 35 which is approximately 2% lower than the California average of 36. In Antioch, 53% of the population over 15 years of age are married, 66% speak English and 21% speak Spanish. 62% of Antioch residents were born in California, 14% were born out of state, 2% were born outside of the United States and 22% were foreign born.