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%−1.5 pts

02Carter County, MTMT1,383+22.0%+31.5 pts

03Broadwater County, MTMT8,493+20.7%−11.5 pts

04Richland County, MTMT11,377+17.9%+27.7 pts

05Flathead County, MTMT115,429+14.8%−11.0 pts

06Madison County, MTMT10,026+12.1%−2.3 pts

07Lewis and Clark County, MTMT75,331+12.0%−5.4 pts

08Yellowstone County, MTMT172,692+11.3%−2.7 pts

09Park County, MTMT18,214+9.9%+2.2 pts

10Ravalli County, MTMT48,582+9.9%−34.4 pts

11Sanders County, MTMT14,062+8.6%−9.3 pts

12Blaine County, MTMT6,860+8.5%+4.3 pts

13Lake County, MTMT33,392+8.3%−17.7 pts

14Missoula County, MTMT123,513+7.9%−13.9 pts

15Granite County, MTMT3,658+7.5%−3.6 pts

16Mineral County, MTMT5,185+7.4%−9.8 pts

17Treasure County, MTMT728+6.1%+7.6 pts

18Jefferson County, MTMT13,329+6.0%−20.6 pts

19Fallon County, MTMT2,959+5.5%+14.1 pts

20Sheridan County, MTMT3,436+4.6%+17.8 pts

21Musselshell County, MTMT5,582+4.2%−5.3 pts

22Carbon County, MTMT11,466+3.9%−14.3 pts

23Cascade County, MTMT85,029+3.8%+0.4 pts

24Roosevelt County, MTMT10,242+3.5%+7.0 pts

25Valley County, MTMT7,385+2.8%+9.7 pts

26Glacier County, MTMT13,463+2.8%−6.5 pts

27Silver Bow County, MTMT36,118+2.7%+0.8 pts

28Teton County, MTMT6,496+2.5%−0.3 pts

29Big Horn County, MTMT12,752+2.0%−9.8 pts

30Meagher County, MTMT2,137+1.9%−4.3 pts

31Custer County, MTMT12,034+1.4%+1.4 pts

32Chouteau County, MTMT5,865+1.4%−8.1 pts

33Beaverhead County, MTMT10,043+1.4%−7.9 pts

34Hill County, MTMT16,167+1.3%+6.9 pts

35Deer Lodge County, MTMT9,709+1.3%+9.7 pts

36Sweet Grass County, MTMT3,762+0.7%−13.7 pts

37Petroleum County, MTMT548+0.4%+5.4 pts

38Lincoln County, MTMT22,328-0.1%−7.8 pts

39McCone County, MTMT1,720-0.3%+12.8 pts

40Dawson County, MTMT8,692-0.3%+4.4 pts

41Phillips County, MTMT4,203-0.8%+10.0 pts

42Powell County, MTMT7,157-1.2%−9.6 pts

43Fergus County, MTMT11,825-1.2%+0.4 pts

44Stillwater County, MTMT9,445-1.7%−27.1 pts

45Judith Basin County, MTMT2,162-2.4%−4.4 pts

46Garfield County, MTMT1,148-2.7%+16.8 pts

47Powder River County, MTMT1,781-2.8%+8.3 pts

48Pondera County, MTMT6,072-4.1%−4.0 pts

49Wheatland County, MTMT2,100-4.6%−5.1 pts

50Daniels County, MTMT1,612-5.1%+5.8 pts

51Toole County, MTMT5,211-6.6%−11.0 pts

52Golden Valley County, MTMT844-6.9%−21.2 pts

53Prairie County, MTMT1,112-7.7%+5.6 pts

54Wibaux County, MTMT885-7.9%+2.5 pts

55Rosebud County, MTMT8,253-9.8%+0.9 pts

56Liberty County, MTMT1,957-16.2%−10.3 pts

SHOWING 1–56 OF 56

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UPDATED 2026-08-08 · DATA: US CENSUS BUREAU DECENNIAL CENSUS