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Population of Counties in Montana (2024)

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2024 Population
Growth Since 2020
Area (mi²)
Density (/mi²)
Yellowstone County171,8163.99%1K65Yellowstone County location
Gallatin County127,8806.93%1K49Gallatin County location
Missoula County122,6873.67%1K47Missoula County location
Flathead County115,47310.1%2K23Flathead County location
Cascade County84,7990.46%1K31Cascade County location
Lewis and Clark County76,2387.11%1.3K22Lewis and Clark County location
Ravalli County48,2998.75%92320Ravalli County location
Silver Bow County36,7734.44%27751Silver Bow County location
Lake County33,8238.21%57523Lake County location
Lincoln County22,28012.9%1.4K6Lincoln County location
Park County18,0534.82%1.1K6Park County location
Hill County16,4341%1.1K6Hill County location
Sanders County13,98412.25%1.1K5Sanders County location
Glacier County13,568-1.29%1.2K5Glacier County location
Jefferson County13,2659.25%6408Jefferson County location
Big Horn County12,676-3.09%1.9K3Big Horn County location
Custer County11,9700.88%1.5K3Custer County location
Fergus County11,8723.46%1.7K3Fergus County location
Carbon County11,60210.44%7916Carbon County location
Richland County11,116-3.62%8055Richland County location
Roosevelt County10,101-6.48%9094Roosevelt County location
Beaverhead County10,0236.83%2.1K2Beaverhead County location
Deer Lodge County9,8024.06%28413Deer Lodge County location
Madison County9,79013.04%1.4K3Madison County location
Stillwater County9,1771.93%6945Stillwater County location
Dawson County8,813-1.24%9164Dawson County location
Broadwater County8,29320.89%4607Broadwater County location
Rosebud County8,168-1.7%1.9K2Rosebud County location
Valley County7,406-1.99%1.9K2Valley County location
Powell County7,1883.54%8983Powell County location
Blaine County6,826-2.58%1.6K2Blaine County location
Teton County6,5144.19%8773Teton County location
Pondera County6,1584.76%6274Pondera County location
Chouteau County5,786-1.92%1.5K1Chouteau County location
Musselshell County5,44714.67%7213Musselshell County location
Toole County5,1894.36%7393Toole County location
Mineral County5,16012.96%4714Mineral County location
Phillips County4,2701.35%2K1Phillips County location
Sweet Grass County3,7993.51%7162Sweet Grass County location
Granite County3,69311.5%6672Granite County location
Sheridan County3,441-2.8%6472Sheridan County location
Fallon County2,938-3%6262Fallon County location
Meagher County2,11610.21%9231Meagher County location
Judith Basin County2,1074.31%7221Judith Basin County location
Wheatland County2,0760%5491Wheatland County location
Liberty County1,9741.02%5521Liberty County location
Powder River County1,7543.42%1.3K1Powder River County location
McCone County1,641-5.03%1K1McCone County location
Daniels County1,621-2%5501Daniels County location
Carter County1,4332.07%1.3K0.43Carter County location
Garfield County1,2042.73%1.8K0.26Garfield County location
Prairie County1,1162.29%6701Prairie County location
Wibaux County893-4.49%3441Wibaux County location
Golden Valley County8442.8%4531Golden Valley County location
Treasure County7904.08%3781Treasure County location
Petroleum County58717.64%6390.35Petroleum County location
showing: 56 rows

There are 56 counties in Montana. The most populous county located in the state of Montana is Yellowstone County, home to Billings, which has a population of 160,137 in 2019. Since the time that the last census was taken in 2010, Yellowstone County has seen an increase in the total population of 7.92%. The only other counties in the state of Montana with a population of more than 100,000 are Missoula County (118,791, Gallatin County (111,876), and Flathead County (102,106). All four counties have experienced substantial population growth of at least 7%; Gallatin County grew the most with a 24.79% growth rate.

Montana Counties with the Fewest Residents

The county with the lowest population in the state of Montana is Petroleum County, which has a population of 513 people. Since the last census in 2010, Petroleum County’s population has seen an increase of 4.91%. Following up after Petroleum County, other small counties in Montana include Treasure County (679), Golden Valley County (826), Wibaux County (1,034), and Prairie County (1,087). Of these counties, Petroleum County experienced the most significant growth while Prairie County had the most dramatic decline with a growth rate of -8.11%.

Montana Counties with Rapid Growth

The county with the most significant growth rate in the state of Montana is Gallatin County, which has seen a population growth of 24.79% since the 2010 census was taken, bringing the population up to 111,876 in 2019. Montana has several other counties that have experienced double-digit growth since the census including Madison County (13.91%), Flathead County (12.37%), and Richland County (11.82%). Toole County has seen the lowest population growth, with a loss of 9.17%. )

Lists of Counties in all States

  1. Montana Census & Economic Information Center
  2. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  3. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  4. American Community Survey (2009 - 2013)
  5. Census QuickFacts
  6. Historical Populations of States and Counties (1790 - 1990)