Frostline.info

Frost line depth in Montana

Estimated frost depth in typical soil runs from 35″ to 59″ across Montana's 56 counties. Pick your county or enter a ZIP code for a local estimate.

Deepest frost

  1. Valley County 59″
  2. Sheridan County 59″
  3. Roosevelt County 58″
  4. Daniels County 58″
  5. Phillips County 57″

Mildest

  1. Sanders County 35″
  2. Mineral County 36″
  3. Ravalli County 37″
  4. Lake County 37″
  5. Lincoln County 39″

Frost depth by county

CountyEst. frost (typical soil)Typical code range
Beaverhead County47″42–60″
Big Horn County46″36–60″
Blaine County56″48–72″
Broadwater County44″36–54″
Carbon County41″36–54″
Carter County47″42–60″
Cascade County47″42–60″
Chouteau County52″42–66″
Custer County52″42–66″
Daniels County58″48–72″
Dawson County54″42–66″
Deer Lodge County40″36–48″
Fallon County52″42–66″
Fergus County48″42–60″
Flathead County40″36–54″
Gallatin County46″36–60″
Garfield County52″42–66″
Glacier County51″42–66″
Golden Valley County44″36–54″
Granite County42″36–54″
Hill County56″48–72″
Jefferson County44″36–54″
Judith Basin County46″36–60″
Lake County37″30–48″
Lewis and Clark County45″36–54″
Liberty County54″42–66″
Lincoln County39″36–48″
Madison County40″36–48″
McCone County55″48–66″
Meagher County43″36–54″
Mineral County36″30–48″
Missoula County39″36–48″
Musselshell County45″36–60″
Park County42″36–54″
Petroleum County47″42–60″
Phillips County57″48–72″
Pondera County50″42–60″
Powder River County48″42–60″
Powell County43″36–54″
Prairie County56″48–72″
Ravalli County37″30–48″
Richland County56″48–72″
Roosevelt County58″48–72″
Rosebud County49″42–60″
Sanders County35″30–48″
Sheridan County59″48–72″
Silver Bow County43″36–54″
Stillwater County42″36–54″
Sweet Grass County40″36–48″
Teton County48″42–60″
Toole County51″42–66″
Treasure County49″42–60″
Valley County59″48–72″
Wheatland County45″36–54″
Wibaux County56″48–66″
Yellowstone County45″36–54″

Common questions

What is the frost line depth in Montana?

It ranges from about 35 inches in the mildest county to 59 inches in the coldest, in typical soil.

Which Montana county has the deepest frost?

Valley County, at about 59 inches in typical soil.