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Idaho soil by county

Across Idaho's mapped land, shrink-swell clay limits houses without basements on 9% and a shallow water table limits basements on 8%.

Highest clay shares: Washington County (33%), Owyhee County (27%), Gooding County (26%), Lewis County (23%), Jefferson County (21%). Highest water-table shares: Latah County (43%), Benewah County (40%), Lewis County (33%), Boundary County (24%), Camas County (22%).

Data as of September 22, 2026 · 44 counties

Ada County: 20%Adams County: 9%Bannock County: no dataBear Lake County: 6%Benewah County: 1%Bingham County: 0%Blaine County: 11%Boise County: 3%Bonner County: 0%Bonneville County: 11%Boundary County: 0%Butte County: 1%Camas County: 19%Canyon County: 1%Caribou County: 13%Cassia County: 3%Clark County: 4%Clearwater County: 1%Custer County: 3%Elmore County: 7%Franklin County: 21%Fremont County: 1%Gem County: 19%Gooding County: 26%Idaho County: 9%Jefferson County: 21%Jerome County: 0%Kootenai County: 2%Latah County: 5%Lemhi County: 10%Lewis County: 23%Lincoln County: 16%Madison County: 0%Minidoka County: 1%Nez Perce County: 7%Oneida County: 5%Owyhee County: 27%Payette County: 4%Power County: 1%Shoshone County: 0%Teton County: 5%Twin Falls County: 13%Valley County: 1%Washington County: 33%
Expansive clay: share of mapped land where shrink-swell clay limits houses without basementsunder 10%10-25%25-40%40-60%60%+
Ada County: 4%Adams County: 7%Bannock County: no dataBear Lake County: 16%Benewah County: 40%Bingham County: 2%Blaine County: 4%Boise County: 2%Bonner County: 14%Bonneville County: 4%Boundary County: 24%Butte County: 2%Camas County: 22%Canyon County: 14%Caribou County: 4%Cassia County: 2%Clark County: 4%Clearwater County: 14%Custer County: 7%Elmore County: 2%Franklin County: 8%Fremont County: 6%Gem County: 9%Gooding County: 0%Idaho County: 12%Jefferson County: 8%Jerome County: 0%Kootenai County: 10%Latah County: 43%Lemhi County: 12%Lewis County: 33%Lincoln County: 1%Madison County: 14%Minidoka County: 7%Nez Perce County: 15%Oneida County: 4%Owyhee County: 2%Payette County: 9%Power County: 2%Shoshone County: 4%Teton County: 12%Twin Falls County: 1%Valley County: 14%Washington County: 3%
High water table: share of mapped land where a shallow water table limits basementsunder 10%10-25%25-40%40-60%60%+

Every county in Idaho

Select a column heading to sort.
Ada County 20% 4% 68% 55 1997
Adams County 9% 7% 94% 0 1986
Bannock County n/a n/a 100% 6 1976
Bear Lake County 6% 16% 100% 0 1974
Benewah County 1% 40% 100% 2 1979
Bingham County under 1% 2% 100% 1 1978
Blaine County 11% 4% 69% 193 1987
Boise County 3% 2% 17% 1 1991
Bonner County under 1% 14% 100% 6 1990
Bonneville County 11% 4% 100% 4 1985
Boundary County under 1% 24% 100% 1 1991
Butte County 1% 2% 95% 0 1971
Camas County 19% 22% 76% 0 1991
Canyon County 1% 14% 11% 8 1999
Caribou County 13% 4% 100% 1 1972
Cassia County 3% 2% 100% 0 1975
Clark County 4% 4% 100% 0 1979
Clearwater County 1% 14% 51% 0 1977
Custer County 3% 7% 4% 0 1986
Elmore County 7% 2% 86% 7 1988
Franklin County 21% 8% 100% 0 1975
Fremont County 1% 6% 100% 6 1979
Gem County 19% 9% 2% 1 1983
Gooding County 26% under 1% 100% 0 1976
Idaho County 9% 12% 19% 2 1977
Jefferson County 21% 8% 100% 0 1994
Jerome County under 1% under 1% 100% 0 1983
Kootenai County 2% 10% 100% 11 1996
Latah County 5% 43% 100% 30 1980
Lemhi County 10% 12% 3% 5 1979
Lewis County 23% 33% 100% 0 1965
Lincoln County 16% 1% 100% 0 1985
Madison County under 1% 14% 100% 0 2002
Minidoka County 1% 7% 100% 3 1976
Nez Perce County 7% 15% 100% 0 1973
Oneida County 5% 4% 100% 1 1971
Owyhee County 27% 2% 99% 0 1984
Payette County 4% 9% 29% 3 1978
Power County 1% 2% 100% 0 1975
Shoshone County under 1% 4% 88% 2 1959
Teton County 5% 12% 100% 1 2001
Twin Falls County 13% 1% 100% 5 1982
Valley County 1% 14% 2% 0 1992
Washington County 33% 3% 95% 8 1975

How these shares are counted

Shares are of mapped land in USDA's soil survey (SSURGO), weighted by each soil's share of every map unit. Drought is the US Drought Monitor's D1-or-worse share on the September 22, 2026 map. Flood losses are FEMA NFIP records since 2016. Sources and methods.