Herrin, IL has a population of 12,868 and is the 3,231st largest city in the United States. The population density is 1,323 per sq mi which is 495% higher than the Illinois average and 1361% higher than the national average. The median age in Herrin is 39 which is approximately 5% higher than the Illinois average of 37. In Herrin, 58% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 78% of Herrin residents were born in Illinois, 21% were born out of state, 0% were born outside of the United States and 1% were foreign born.