Laddonia is a city in Audrain County, Missouri, United States.

[6] It was named for Amos Ladd, an early settler, and his wife, Onia.

[9] According to the United States Census Bureau, the city has a total area of 0.65 square miles (1.68 km2), all land.

There were 274 housing units at an average density of 421.5 per square mile (162.7/km2).

33.6% of all households were made up of individuals, and 12.4% had someone living alone who was 65 years of age or older.

There were 278 housing units at an average density of 503.9 per square mile (194.6/km2).

28.7% of all households were made up of individuals, and 18.1% had someone living alone who was 65 years of age or older.