Ionia is a village in northern Benton and southern Pettis counties in the U.S. state of Missouri.

[4] Ionia is located at along the Pettis-Benton county line on Missouri Route P 1.5 miles west of US Route 65 and approximately seven miles west-northwest of Cole Camp.

[6] According to the United States Census Bureau, the village has a total area of 0.15 square miles (0.39 km2), all land.

44.2% of all households were made up of individuals, and 23.3% had someone living alone who was 65 years of age or older.

34.0% of all households were made up of individuals, and 17.0% had someone living alone who was 65 years of age or older.

There were 19.2% of families and 27.6% of the population living below the poverty line, including 44.4% of under eighteens and 12.5% of those over 64.