Mainville, PA has a population of 114 and is the 26,574th largest city in the United States. The population density is 164 per sq mi which is 41% lower than the Pennsylvania average and 81% higher than the national average. The median age in Mainville is 54 which is approximately 33% higher than the Pennsylvania average of 41. In Mainville, 77% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 96% of Mainville residents were born in Pennsylvania, 4% were born out of state, 0% were born outside of the United States and 0% were foreign born.