St. Henry, OH has a population of 2,646 and is the 9,479th largest city in the United States. The population density is 1,650 per sq mi which is 541% higher than the Ohio average and 1721% higher than the national average. The median age in St. Henry is 35 which is approximately 11% lower than the Ohio average of 39. In St. Henry, 70% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 92% of St. Henry residents were born in Ohio, 5% were born out of state, 0% were born outside of the United States and 3% were foreign born.