Auburn, IN has a population of 12,758 and is the 3,256th largest city in the United States. The population density is 1,668 per sq mi which is 829% higher than the Indiana average and 1741% higher than the national average. The median age in Auburn is 40 which is approximately 6% higher than the Indiana average of 37. In Auburn, 58% of the population over 15 years of age are married, 97% speak English and 1% speak Spanish. 69% of Auburn residents were born in Indiana, 29% were born out of state, 0% were born outside of the United States and 2% were foreign born.