San Diego, CA has a population of 1,374,812 and is the 8th largest city in the United States. The population density is 4,233 per sq mi which is 1722% higher than the California average and 4573% higher than the national average. The median age in San Diego is 34 which is approximately 5% lower than the California average of 36. In San Diego, 48% of the population over 15 years of age are married, 59% speak English and 23% speak Spanish. 45% of San Diego residents were born in California, 26% were born out of state, 2% were born outside of the United States and 26% were foreign born.