Fairfax is a city in Clark Township, Atchison County, Missouri, United States.

There were 343 housing units at an average density of 729.8 per square mile (281.8/km2).

The racial makeup of the city was 98.4% White, 0.6% African American, 0.3% Asian, and 0.6% from two or more races.

30.9% of all households were made up of individuals, and 19% had someone living alone who was 65 years of age or older.

There were 342 housing units at an average density of 713.3 per square mile (275.4/km2).

37.9% of all households were made up of individuals, and 24.6% had someone living alone who was 65 years of age or older.