Ionia, MI has a population of 11,396 and is the 3,560th largest city in the United States. The population density is 2,149 per sq mi which is 2031% higher than the Michigan average and 2272% higher than the national average. The median age in Ionia is 34 which is approximately 13% lower than the Michigan average of 40. In Ionia, 33% of the population over 15 years of age are married, 95% speak English and 3% speak Spanish. 85% of Ionia residents were born in Michigan, 13% were born out of state, 0% were born outside of the United States and 1% were foreign born.