Hercules, CA has a population of 25,011 and is the 1,733rd largest city in the United States. The population density is 3,902 per sq mi which is 1579% higher than the California average and 4207% higher than the national average. The median age in Hercules is 40 which is approximately 11% higher than the California average of 36. In Hercules, 58% of the population over 15 years of age are married, 53% speak English and 9% speak Spanish. 50% of Hercules residents were born in California, 12% were born out of state, 3% were born outside of the United States and 35% were foreign born.