Senecaville, OH has a population of 428 and is the 20,495th largest city in the United States. The population density is 901 per sq mi which is 250% higher than the Ohio average and 895% higher than the national average. The median age in Senecaville is 32 which is approximately 19% lower than the Ohio average of 39. In Senecaville, 52% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 86% of Senecaville residents were born in Ohio, 14% were born out of state, 0% were born outside of the United States and 0% were foreign born.