Newtonsville, OH has a population of 442 and is the 20,323rd largest city in the United States. The population density is 2,327 per sq mi which is 708% higher than the Ohio average and 2469% higher than the national average. The median age in Newtonsville is 35 which is approximately 11% lower than the Ohio average of 39. In Newtonsville, 51% of the population over 15 years of age are married, 98% speak English and 2% speak Spanish. 89% of Newtonsville residents were born in Ohio, 9% were born out of state, 2% were born outside of the United States and 0% were foreign born.