Hartsville, IN has a population of 378 and is the 21,188th largest city in the United States. The population density is 1,164 per sq mi which is 549% higher than the Indiana average and 1185% higher than the national average. The median age in Hartsville is 35 which is approximately 6% lower than the Indiana average of 37. In Hartsville, 52% of the population over 15 years of age are married, 99% speak English and 1% speak Spanish. 87% of Hartsville residents were born in Indiana, 11% were born out of state, 0% were born outside of the United States and 1% were foreign born.