Frostline.info

Frost line depth in Idaho

Estimated frost depth in typical soil runs from 26″ to 48″ across Idaho's 44 counties. Pick your county or enter a ZIP code for a local estimate.

Deepest frost

  1. Butte County 48″
  2. Bear Lake County 48″
  3. Jefferson County 47″
  4. Fremont County 47″
  5. Bonneville County 46″

Mildest

  1. Clearwater County 26″
  2. Idaho County 28″
  3. Elmore County 28″
  4. Nez Perce County 28″
  5. Owyhee County 29″

Frost depth by county

CountyEst. frost (typical soil)Typical code range
Ada County30″24–36″
Adams County39″30–48″
Bannock County40″36–48″
Bear Lake County48″42–60″
Benewah County33″30–42″
Bingham County42″36–54″
Blaine County42″36–54″
Boise County33″30–42″
Bonner County33″30–42″
Bonneville County46″36–60″
Boundary County34″30–42″
Butte County48″42–60″
Camas County45″36–60″
Canyon County30″24–36″
Caribou County44″36–54″
Cassia County31″30–42″
Clark County46″36–60″
Clearwater County26″24–36″
Custer County44″36–54″
Elmore County28″24–36″
Franklin County40″36–48″
Fremont County47″42–60″
Gem County32″30–42″
Gooding County31″24–42″
Idaho County28″24–36″
Jefferson County47″42–60″
Jerome County31″24–42″
Kootenai County30″24–36″
Latah County32″30–42″
Lemhi County43″36–54″
Lewis County30″24–36″
Lincoln County37″30–48″
Madison County45″36–54″
Minidoka County34″30–42″
Nez Perce County28″24–36″
Oneida County39″36–48″
Owyhee County29″24–36″
Payette County33″30–42″
Power County38″30–48″
Shoshone County32″30–42″
Teton County45″36–54″
Twin Falls County30″24–36″
Valley County41″36–54″
Washington County37″30–48″

Common questions

What is the frost line depth in Idaho?

It ranges from about 26 inches in the mildest county to 48 inches in the coldest, in typical soil.

Which Idaho county has the deepest frost?

Butte County, at about 48 inches in typical soil.