[3][4] Clark County is part of the Fort Madison–Keokuk, IA-IL-MO Micropolitan Statistical Area.

Missouri folklorist Margot Ford McMillen wrote that early settlers were attracted by Clark County's good and inexpensive agricultural land.

26.40% of all households were made up of individuals, and 13.60% had someone living alone who was 65 years of age or older.

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

As of 2018, Republicans hold nine of fourteen of the elected positions in the county.