RANKING · 2025 ESTIMATES · 56 SHOWN OF 56

Fastest shrinking, Montana counties

Montana counties with the steepest population decline from the 2020 census to 2025. 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 growing Most population gained Most population lost Most densely populated Most sparsely populated

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION GROWTHVS 2000

01Wibaux County, MTMT885-5.5%−46%

02Roosevelt County, MTMT10,242-5.1%+48%

03Treasure County, MTMT728-4.5%+200%

04Fallon County, MTMT2,959-3.0%−66%

05Daniels County, MTMT1,612-3.0%−73%

06Sheridan County, MTMT3,436-2.9%−78%

07Big Horn County, MTMT12,752-2.8%−124%

08Dawson County, MTMT8,692-2.8%−41%

09Blaine County, MTMT6,860-2.6%−163%

10Valley County, MTMT7,385-2.5%−63%

11Glacier County, MTMT13,463-2.3%−125%

12Carter County, MTMT1,383-2.3%−76%

13Garfield County, MTMT1,148-2.1%−89%

14Richland County, MTMT11,377-1.0%−90%

15Rosebud County, MTMT8,253-0.9%−91%

16Hill County, MTMT16,167-0.9%−84%

17McCone County, MTMT1,720-0.5%−96%

18Chouteau County, MTMT5,865-0.5%−105%

19Phillips County, MTMT4,203-0.3%−97%

20Liberty County, MTMT1,957-0.1%−98%

21Cascade County, MTMT85,029+0.7%−79%

22Custer County, MTMT12,034+1.4%−16561%

23Wheatland County, MTMT2,100+1.5%+159%

24Prairie County, MTMT1,112+2.2%−117%

25Sweet Grass County, MTMT3,762+2.3%−84%

26Golden Valley County, MTMT844+2.6%−82%

27Silver Bow County, MTMT36,118+2.8%+43%

28Pondera County, MTMT6,072+3.0%−2209%

29Powell County, MTMT7,157+3.0%−64%

30Deer Lodge County, MTMT9,709+3.1%−136%

31Fergus County, MTMT11,825+3.3%−311%

32Teton County, MTMT6,496+4.3%+56%

33Missoula County, MTMT123,513+4.7%−78%

34Toole County, MTMT5,211+4.8%+10%

35Yellowstone County, MTMT172,692+4.8%−66%

36Powder River County, MTMT1,781+5.1%−146%

37Stillwater County, MTMT9,445+5.4%−79%

38Park County, MTMT18,214+6.0%−23%

39Lewis and Clark County, MTMT75,331+6.1%−65%

40Judith Basin County, MTMT2,162+6.9%+234%

41Beaverhead County, MTMT10,043+7.2%−22%

42Lake County, MTMT33,392+7.3%−72%

43Gallatin County, MTMT128,740+8.2%−76%

44Carbon County, MTMT11,466+9.5%−48%

45Ravalli County, MTMT48,582+10.0%−77%

46Jefferson County, MTMT13,329+10.3%−61%

47Petroleum County, MTMT548+10.5%−309%

48Granite County, MTMT3,658+10.5%−5%

49Flathead County, MTMT115,429+10.6%−59%

50Meagher County, MTMT2,137+10.9%+75%

51Sanders County, MTMT14,062+13.4%−25%

52Lincoln County, MTMT22,328+13.5%+74%

53Mineral County, MTMT5,185+14.3%−16%

54Madison County, MTMT10,026+16.3%+13%

55Musselshell County, MTMT5,582+18.0%+89%

56Broadwater County, MTMT8,493+25.4%−21%

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU POPULATION ESTIMATES