Carbon Hill, IL has a population of 380 and is the 21,150th largest city in the United States. The population density is 2,065 per sq mi which is 829% higher than the Illinois average and 2179% higher than the national average. The median age in Carbon Hill is 35 which is approximately 7% lower than the Illinois average of 37. In Carbon Hill, 52% of the population over 15 years of age are married, 96% speak English and 3% speak Spanish. 91% of Carbon Hill residents were born in Illinois, 8% were born out of state, 0% were born outside of the United States and 1% were foreign born.