RANKING · 2020 CENSUS · 56 SHOWN OF 56

Fastest growing, Montana counties · 2020

Montana counties ranked by population growth from the 2010 census to 2020. This list covers the 56 counties in Montana that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest shrinking Most population gained Most population lost Most densely populated Most sparsely populated

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION GROWTHVS 2000

01Gallatin County, MTMT128,740+32.9%−4%

02Carter County, MTMT1,383+22.0%−331%

03Broadwater County, MTMT8,493+20.7%−36%

04Richland County, MTMT11,377+17.9%−283%

05Flathead County, MTMT115,429+14.8%−43%

06Madison County, MTMT10,026+12.1%−16%

07Lewis and Clark County, MTMT75,331+12.0%−31%

08Yellowstone County, MTMT172,692+11.3%−19%

09Park County, MTMT18,214+9.9%+28%

10Ravalli County, MTMT48,582+9.9%−78%

11Sanders County, MTMT14,062+8.6%−52%

12Blaine County, MTMT6,860+8.5%+104%

13Lake County, MTMT33,392+8.3%−68%

14Missoula County, MTMT123,513+7.9%−64%

15Granite County, MTMT3,658+7.5%−33%

16Mineral County, MTMT5,185+7.4%−57%

17Treasure County, MTMT728+6.1%−512%

18Jefferson County, MTMT13,329+6.0%−78%

19Fallon County, MTMT2,959+5.5%−164%

20Sheridan County, MTMT3,436+4.6%−135%

21Musselshell County, MTMT5,582+4.2%−56%

22Carbon County, MTMT11,466+3.9%−78%

23Cascade County, MTMT85,029+3.8%+11%

24Roosevelt County, MTMT10,242+3.5%−203%

25Valley County, MTMT7,385+2.8%−141%

26Glacier County, MTMT13,463+2.8%−70%

27Silver Bow County, MTMT36,118+2.7%+39%

28Teton County, MTMT6,496+2.5%−9%

29Big Horn County, MTMT12,752+2.0%−83%

30Meagher County, MTMT2,137+1.9%−69%

31Custer County, MTMT12,034+1.4%−16897%

32Chouteau County, MTMT5,865+1.4%−85%

33Beaverhead County, MTMT10,043+1.4%−85%

34Hill County, MTMT16,167+1.3%−124%

35Deer Lodge County, MTMT9,709+1.3%−116%

36Sweet Grass County, MTMT3,762+0.7%−95%

37Petroleum County, MTMT548+0.4%−108%

38Lincoln County, MTMT22,328-0.1%−101%

39McCone County, MTMT1,720-0.3%−98%

40Dawson County, MTMT8,692-0.3%−94%

41Phillips County, MTMT4,203-0.8%−92%

42Powell County, MTMT7,157-1.2%−114%

43Fergus County, MTMT11,825-1.2%−23%

44Stillwater County, MTMT9,445-1.7%−107%

45Judith Basin County, MTMT2,162-2.4%−215%

46Garfield County, MTMT1,148-2.7%−86%

47Powder River County, MTMT1,781-2.8%−75%

48Pondera County, MTMT6,072-4.1%+2862%

49Wheatland County, MTMT2,100-4.6%−889%

50Daniels County, MTMT1,612-5.1%−53%

51Toole County, MTMT5,211-6.6%−251%

52Golden Valley County, MTMT844-6.9%−148%

53Prairie County, MTMT1,112-7.7%−42%

54Wibaux County, MTMT885-7.9%−24%

55Rosebud County, MTMT8,253-9.8%−8%

56Liberty County, MTMT1,957-16.2%+172%

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS