Auburn, WA has a population of 75,607 and is the 466th largest city in the United States. The population density is 2,563 per sq mi which is 2551% higher than the Washington average and 2729% higher than the national average. The median age in Auburn is 35 which is approximately 7% lower than the Washington average of 38. In Auburn, 53% of the population over 15 years of age are married, 74% speak English and 10% speak Spanish. 49% of Auburn residents were born in Washington, 31% were born out of state, 2% were born outside of the United States and 18% were foreign born.