Thorntown, IN has a population of 1,637 and is the 12,194th largest city in the United States. The population density is 2,711 per sq mi which is 1410% higher than the Indiana average and 2893% higher than the national average. The median age in Thorntown is 36 which is approximately 4% lower than the Indiana average of 37. In Thorntown, 60% of the population over 15 years of age are married, 96% speak English and 4% speak Spanish. 80% of Thorntown residents were born in Indiana, 17% were born out of state, 2% were born outside of the United States and 2% were foreign born.