Sulphur Springs, IN has a population of 347 and is the 21,670th largest city in the United States. The population density is 492 per sq mi which is 174% higher than the Indiana average and 443% higher than the national average. The median age in Sulphur Springs is 36 which is approximately 3% lower than the Indiana average of 37. In Sulphur Springs, 59% of the population over 15 years of age are married, 97% speak English and 2% speak Spanish. 84% of Sulphur Springs residents were born in Indiana, 15% were born out of state, 1% were born outside of the United States and 0% were foreign born.