RANKING · 2025 ESTIMATES · 56 SHOWN OF 56

Most population lost, Montana counties

Montana counties that lost the most residents from the 2020 census to 2025, by raw count of people rather than percentage. This list covers the 56 counties in Montana that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION CHANGEVS 2000

01Roosevelt County, MTMT10,242-552+46%

02Big Horn County, MTMT12,752-372−128%

03Glacier County, MTMT13,463-315−128%

04Dawson County, MTMT8,692-248−44%

05Valley County, MTMT7,385-193−66%

06Blaine County, MTMT6,860-184−165%

07Hill County, MTMT16,167-142−86%

08Richland County, MTMT11,377-114−89%

09Sheridan County, MTMT3,436-103−84%

10Fallon County, MTMT2,959-90−66%

11Rosebud County, MTMT8,253-76−93%

12Wibaux County, MTMT885-52−58%

13Daniels County, MTMT1,612-49−80%

14Treasure County, MTMT728-34+162%

15Carter County, MTMT1,383-32−78%

16Chouteau County, MTMT5,865-30−106%

17Garfield County, MTMT1,148-25−92%

18Phillips County, MTMT4,203-14−98%

19McCone County, MTMT1,720-9−97%

20Liberty County, MTMT1,957-2−99%

21Golden Valley County, MTMT844+21−84%

22Prairie County, MTMT1,112+24−113%

23Wheatland County, MTMT2,100+31+138%

24Petroleum County, MTMT548+52−300%

25Sweet Grass County, MTMT3,762+84−82%

26Powder River County, MTMT1,781+87−138%

27Judith Basin County, MTMT2,162+139+196%

28Custer County, MTMT12,034+167−16800%

29Pondera County, MTMT6,072+174−2033%

30Meagher County, MTMT2,137+210+86%

31Powell County, MTMT7,157+211−62%

32Toole County, MTMT5,211+240+9%

33Teton County, MTMT6,496+270+55%

34Deer Lodge County, MTMT9,709+288−133%

35Granite County, MTMT3,658+349+24%

36Fergus County, MTMT11,825+379−299%

37Stillwater County, MTMT9,445+482−71%

38Cascade County, MTMT85,029+615−77%

39Mineral County, MTMT5,185+650+14%

40Beaverhead County, MTMT10,043+672−14%

41Musselshell County, MTMT5,582+852+118%

42Silver Bow County, MTMT36,118+985+48%

43Carbon County, MTMT11,466+993−33%

44Park County, MTMT18,214+1,023−10%

45Jefferson County, MTMT13,329+1,244−41%

46Madison County, MTMT10,026+1,403+63%

47Sanders County, MTMT14,062+1,662+7%

48Broadwater County, MTMT8,493+1,719+61%

49Lake County, MTMT33,392+2,258−59%

50Lincoln County, MTMT22,328+2,651+96%

51Lewis and Clark County, MTMT75,331+4,358−47%

52Ravalli County, MTMT48,582+4,408−60%

53Missoula County, MTMT123,513+5,591−67%

54Yellowstone County, MTMT172,692+7,961−50%

55Gallatin County, MTMT128,740+9,780−44%

56Flathead County, MTMT115,429+11,072−27%

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