RANKING · 2010 CENSUS · 56 SHOWN OF 56

Fastest shrinking, Montana counties · 2010

Montana counties with the steepest population decline since the prior decennial census. 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 densely populated Most sparsely populated Best broadband access Worst broadband access

YEAR2000 2010 2020

RANKPLACESTATEPOPPOPULATION GROWTHVS 2000

01Sheridan County, MTMT3,436-17.6%+33%

02Treasure County, MTMT728-16.6%+1017%

03Golden Valley County, MTMT844-15.2%−206%

04Carter County, MTMT1,383-14.7%+55%

05Daniels County, MTMT1,612-13.2%+20%

06McCone County, MTMT1,720-12.3%−6%

07Judith Basin County, MTMT2,162-11.0%−636%

08Phillips County, MTMT4,203-7.6%−31%

09Blaine County, MTMT6,860-7.4%−277%

10Powder River County, MTMT1,781-6.2%−44%

11Teton County, MTMT6,496-5.8%−308%

12Garfield County, MTMT1,148-5.7%−71%

13Wibaux County, MTMT885-4.8%−54%

14Pondera County, MTMT6,072-4.2%+2915%

15Wheatland County, MTMT2,100-4.0%−796%

16Valley County, MTMT7,385-4.0%−42%

17Hill County, MTMT16,167-3.5%−38%

18Chouteau County, MTMT5,865-2.6%−128%

19Fergus County, MTMT11,825-2.6%+64%

20Powell County, MTMT7,157-2.1%−125%

21Meagher County, MTMT2,137-2.1%−134%

22Roosevelt County, MTMT10,242-1.8%−47%

23Prairie County, MTMT1,112-1.7%−87%

24Rosebud County, MTMT8,253-1.6%−85%

25Deer Lodge County, MTMT9,709-1.3%−85%

26Silver Bow County, MTMT36,118-1.2%−160%

27Dawson County, MTMT8,692-1.0%−78%

28Park County, MTMT18,214-0.4%−105%

29Custer County, MTMT12,034+0.0%−400%

30Petroleum County, MTMT548+0.2%−104%

31Beaverhead County, MTMT10,043+0.5%−95%

32Richland County, MTMT11,377+0.8%−108%

33Musselshell County, MTMT5,582+0.9%−90%

34Toole County, MTMT5,211+1.1%−75%

35Glacier County, MTMT13,463+1.1%−88%

36Sweet Grass County, MTMT3,762+1.2%−92%

37Cascade County, MTMT85,029+1.2%−65%

38Big Horn County, MTMT12,752+1.5%−87%

39Fallon County, MTMT2,959+1.9%−122%

40Lincoln County, MTMT22,328+4.5%−42%

41Carbon County, MTMT11,466+5.5%−70%

42Liberty County, MTMT1,957+8.4%−241%

43Lake County, MTMT33,392+8.4%−67%

44Mineral County, MTMT5,185+8.7%−49%

45Granite County, MTMT3,658+8.8%−21%

46Stillwater County, MTMT9,445+11.3%−56%

47Ravalli County, MTMT48,582+11.5%−74%

48Sanders County, MTMT14,062+11.6%−35%

49Madison County, MTMT10,026+12.3%−15%

50Jefferson County, MTMT13,329+13.5%−49%

51Lewis and Clark County, MTMT75,331+13.8%−20%

52Missoula County, MTMT123,513+14.1%−35%

53Yellowstone County, MTMT172,692+14.4%+2%

54Flathead County, MTMT115,429+22.1%−14%

55Broadwater County, MTMT8,493+28.0%−13%

56Gallatin County, MTMT128,740+32.0%−7%

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UPDATED 2026-06-02 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES