Hartwell is a former village and census-designated place in Henry County, Missouri, United States.

A post office called Hartwell was established in 1887, and remained in operation until 1968.

[6] According to the United States Census Bureau, the CDP has a total area of 0.48 square miles (1.24 km2), all land.

There were 5 housing units at an average density of 10.4 per square mile (4.0/km2).

There were 5 housing units at an average density of 10.5 per square mile (4.1/km2).

40.0% of all households were made up of individuals, and 20.0% had someone living alone who was 65 years of age or older.