Auburn, CA has a population of 13,858 and is the 3,021st largest city in the United States. The population density is 1,937 per sq mi which is 734% higher than the California average and 2038% higher than the national average. The median age in Auburn is 50 which is approximately 38% higher than the California average of 36. In Auburn, 59% of the population over 15 years of age are married, 90% speak English and 6% speak Spanish. 66% of Auburn residents were born in California, 27% were born out of state, 1% were born outside of the United States and 7% were foreign born.