Plainville, IN has a population of 540 and is the 19,099th largest city in the United States. The population density is 1,539 per sq mi which is 758% higher than the Indiana average and 1599% higher than the national average. The median age in Plainville is 43 which is approximately 16% higher than the Indiana average of 37. In Plainville, 72% of the population over 15 years of age are married, 94% speak English and 0% speak Spanish. 86% of Plainville residents were born in Indiana, 12% were born out of state, 1% were born outside of the United States and 0% were foreign born.