[3] Johnson County comprises the Warrensburg Micropolitan Statistical Area, which is also included in the Kansas City-Overland Park-Kansas City, MO-KS Combined Statistical Area.

22.70% of all households were made up of individuals, and 7.10% had someone living alone who was 65 years of age or older.

The Republican Party predominantly controls politics at the local level in Johnson County.

Republicans hold all elected offices in Johnson County.

Johnson County is divided into four legislative districts in the Missouri House of Representatives, all of which are held by Republicans.