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Montana soil by county

Across Montana's mapped land, shrink-swell clay limits houses without basements on 23% and a shallow water table limits basements on 3%.

Highest clay shares: Phillips County (64%), Petroleum County (57%), Carter County (52%), Fergus County (51%), Valley County (51%). Highest water-table shares: Deer Lodge County (10%), Beaverhead County (9%), Gallatin County (9%), Ravalli County (8%), Teton County (8%).

Data as of September 22, 2026 · 56 counties

Beaverhead County: 6%Big Horn County: 30%Blaine County: 44%Broadwater County: 1%Carbon County: 30%Carter County: 52%Cascade County: 35%Chouteau County: 39%Custer County: 19%Daniels County: 3%Dawson County: 8%Deer Lodge County: 6%Fallon County: 21%Fergus County: 51%Flathead County: 1%Gallatin County: 9%Garfield County: 22%Glacier County: 22%Golden Valley County: 26%Granite County: 6%Hill County: 29%Jefferson County: 1%Judith Basin County: 37%Lake County: 2%Lewis and Clark County: 6%Liberty County: 34%Lincoln County: no dataMadison County: 3%McCone County: 12%Meagher County: no dataMineral County: 0%Missoula County: 1%Musselshell County: 24%Park County: 11%Petroleum County: 57%Phillips County: 64%Pondera County: 35%Powder River County: 30%Powell County: 10%Prairie County: 10%Ravalli County: 0%Richland County: 8%Roosevelt County: 10%Rosebud County: 25%Sanders County: 2%Sheridan County: 6%Silver Bow County: 2%Stillwater County: 26%Sweet Grass County: 16%Teton County: 23%Toole County: 29%Treasure County: 44%Valley County: 51%Wheatland County: no dataWibaux County: 22%Yellowstone County: 23%
Expansive clay: share of mapped land where shrink-swell clay limits houses without basementsunder 10%10-25%25-40%40-60%60%+
Beaverhead County: 9%Big Horn County: 1%Blaine County: 2%Broadwater County: 3%Carbon County: 2%Carter County: 1%Cascade County: 2%Chouteau County: 2%Custer County: 1%Daniels County: 1%Dawson County: 1%Deer Lodge County: 10%Fallon County: 1%Fergus County: 3%Flathead County: 3%Gallatin County: 9%Garfield County: 0%Glacier County: 2%Golden Valley County: 2%Granite County: 7%Hill County: 3%Jefferson County: 7%Judith Basin County: 4%Lake County: 3%Lewis and Clark County: 3%Liberty County: 3%Lincoln County: no dataMadison County: 4%McCone County: 0%Meagher County: no dataMineral County: 4%Missoula County: 3%Musselshell County: 1%Park County: 4%Petroleum County: 0%Phillips County: 2%Pondera County: 4%Powder River County: 0%Powell County: 6%Prairie County: 1%Ravalli County: 8%Richland County: 2%Roosevelt County: 2%Rosebud County: 0%Sanders County: 3%Sheridan County: 2%Silver Bow County: 5%Stillwater County: 5%Sweet Grass County: 5%Teton County: 8%Toole County: 3%Treasure County: 4%Valley County: 2%Wheatland County: no dataWibaux County: 2%Yellowstone 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 Montana

Select a column heading to sort.
Beaverhead County 6% 9% 46% 0 1979
Big Horn County 30% 1% 100% 0 1976
Blaine County 44% 2% 21% 1 1972
Broadwater County 1% 3% 0% 0 2001
Carbon County 30% 2% 100% 23 1977
Carter County 52% 1% 100% 0 1975
Cascade County 35% 2% 3% 18 1970
Chouteau County 39% 2% 0% 0 1968
Custer County 19% 1% 97% 6 1965
Daniels County 3% 1% 0% 0 1958
Dawson County 8% 1% 99% 2 1966
Deer Lodge County 6% 10% 0% 1 1954
Fallon County 21% 1% 100% 0 1982
Fergus County 51% 3% 84% 1 1966
Flathead County 1% 3% 0% 12 1991
Gallatin County 9% 9% 71% 13 1998
Garfield County 22% under 1% 11% 5 1978
Glacier County 22% 2% 0% 0 1974
Golden Valley County 26% 2% 100% 0 1974
Granite County 6% 7% 0% 0 1980
Hill County 29% 3% 0% 2 1971
Jefferson County 1% 7% 16% 0 1990
Judith Basin County 37% 4% 64% 0 1967
Lake County 2% 3% 0% 0 1986
Lewis and Clark County 6% 3% 0% 40 1982
Liberty County 34% 3% 0% 3 1966
Lincoln County n/a n/a 3% 3 1982
Madison County 3% 4% 100% 0 1995
McCone County 12% under 1% 12% 0 1964
Meagher County n/a n/a 71% 1 1976
Mineral County under 1% 4% 4% 0 1983
Missoula County 1% 3% 0% 39 1985
Musselshell County 24% 1% 100% 0 1975
Park County 11% 4% 94% 36 1980
Petroleum County 57% under 1% 41% 0 1983
Phillips County 64% 2% 7% 4 1974
Pondera County 35% 4% 0% 0 1968
Powder River County 30% under 1% 100% 0 1976
Powell County 10% 6% 0% 1 1966
Prairie County 10% 1% 68% 0 1957
Ravalli County under 1% 8% 0% 2 1991
Richland County 8% 2% 100% 3 1980
Roosevelt County 10% 2% 43% 0 1974
Rosebud County 25% under 1% 97% 2 1978
Sanders County 2% 3% 5% 0 1992
Sheridan County 6% 2% 5% 0 1963
Silver Bow County 2% 5% 60% 0 1956
Stillwater County 26% 5% 100% 35 1986
Sweet Grass County 16% 5% 100% 2 1979
Teton County 23% 8% 0% 1 1962
Toole County 29% 3% 0% 0 1966
Treasure County 44% 4% 100% 0 1972
Valley County 51% 2% 0% 7 1966
Wheatland County n/a n/a 100% 2 1958
Wibaux County 22% 2% 100% 0 1973
Yellowstone County 23% 3% 100% 46 1982

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.