Carbon, IN has a population of 388 and is the 21,037th largest city in the United States. The population density is 2,437 per sq mi which is 1258% higher than the Indiana average and 2590% higher than the national average. The median age in Carbon is 34 which is approximately 10% lower than the Indiana average of 37. In Carbon, 56% of the population over 15 years of age are married, 99% speak English and 1% speak Spanish. 91% of Carbon residents were born in Indiana, 9% were born out of state, 0% were born outside of the United States and 0% were foreign born.