Clark County

Clark County is the name of twelve counties in the United States. Most, though not all, are named after two brothers: military hero George Rogers Clark in the Midwest, and explorer William Clark in the West.
 Clark County, Arkansas
 Clark County, Idaho
 Clark County, Illinois
 Clark County, Indiana
 Clark County, Kansas
 Clark County, Kentucky
 Clark County, Missouri
 Clark County, Nevada, the most populous county bearing the name Clark, containing Las Vegas
 Clark County, Ohio
 Clark County, South Dakota
 Clark County, Washington
 Clark County, Wisconsin

 Other 
 Clarke County
 Lewis and Clark County, Montana