Population of Counties in Montana (2018)

Name 2018 Population Growth Since 2010
Yellowstone County158,9807.16%
Missoula County117,4417.32%
Gallatin County107,81020.32%
Flathead County100,00010.07%
Cascade County81,6540.20%
Lewis and Clark County67,7736.62%
Ravalli County42,5635.58%
Silver Bow County34,6021.13%
Lake County30,2735.17%
Lincoln County19,440-1.30%
Hill County16,4631.97%
Park County16,3534.85%
Glacier County13,6401.67%
Big Horn County13,3603.47%
Jefferson County11,8914.25%
Custer County11,7210.25%
Sanders County11,7112.78%
Fergus County11,291-2.50%
Roosevelt County11,0986.27%
Richland County11,03913.12%
Carbon County10,6966.30%
Beaverhead County9,4341.96%
Stillwater County9,4193.11%
Rosebud County9,248-0.03%
Deer Lodge County9,106-1.97%
Dawson County8,9500.01%
Madison County8,1756.21%
Valley County7,4330.76%
Powell County6,795-3.09%
Blaine County6,7083.15%
Teton County6,0850.21%
Pondera County5,960-3.22%
Broadwater County5,9365.30%
Chouteau County5,765-0.74%
Toole County4,886-8.55%
Musselshell County4,6391.84%
Mineral County4,2550.76%
Phillips County4,119-3.17%
Sweet Grass County3,6912.02%
Sheridan County3,4693.00%
Granite County3,3589.03%
Fallon County3,0094.15%
Liberty County2,4273.41%
Wheatland County2,140-0.74%
Judith Basin County1,961-5.36%
Meagher County1,851-1.44%
Powder River County1,7520.75%
Daniels County1,737-0.69%
McCone County1,718-1.55%
Garfield County1,2938.47%
Carter County1,2225.34%
Prairie County1,109-6.26%
Wibaux County1,0201.19%
Golden Valley County822-6.48%
Treasure County679-5.43%
Petroleum County5235.66%