Tiffin, OH has a population of 17,701 and is the 2,445th largest city in the United States. The population density is 2,578 per sq mi which is 901% higher than the Ohio average and 2745% higher than the national average. The median age in Tiffin is 35 which is approximately 11% lower than the Ohio average of 39. In Tiffin, 48% of the population over 15 years of age are married, 96% speak English and 1% speak Spanish. 82% of Tiffin residents were born in Ohio, 14% were born out of state, 1% were born outside of the United States and 3% were foreign born.