THE CLARK COUNTY LAND BRIEF
Land in the
Eastern Snake River Basalt Plains setting.
Clark County has 1,763.1 square miles of land in Idaho. 6 mapped landscape regions meet across Clark County: Eastern Snake River Basalt Plains, Dry Gneissic-Schistose-Volcanic Hills, Barren Mountains, among others.
The Snake River Plain is lower and gentler than its surrounding mountains. Alluvial valleys, sagebrush-covered plains, low hills and scattered lava fields form its principal landscape patterns.
Regional context: Snake River Plain ↗ · Regional mapping across the county footprint
Where the landscape changes
Clark County intersects 6 mapped regional units. The largest mapped shares are:
- Eastern Snake River Basalt Plains34.5%
- Dry Gneissic-Schistose-Volcanic Hills28.6%
- Barren Mountains22.4%
- Dry Intermontane Sagebrush Valleys11.3%
- Upper Snake River Plain2.1%
Middle Rockies in Clark County
Forested mountain ranges rise above grassy or shrubby intermountain valleys. The Middle Rockies combine alpine high country, partly wooded foothills and valleys supplied by mountain streams.
Read the regional source ↗Finding your parcel within Clark County
The atlas lists 2 cities, towns, townships, and Census communities associated with Clark County, including Dubois, Spencer. The list includes overlapping geography types and does not divide the county into exclusive service areas.
Clark County by land and water
The Census records 0.96 square miles of water within Clark County, or 0.1% of its total area. That share is close to Clark County’s 0.1%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, Clark County has 1,543.9 times the land area of nearby Spencer city (1.14 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Butte County, Fremont County, Jefferson County, Lemhi County within Idaho. A tract near one of these lines should be matched to the county identifier on its own records.

