RANKING · 2010 CENSUS · 56 SHOWN OF 56

Most population lost, Montana counties · 2010

Montana counties that lost the most residents from the 2000 census to 2010, 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

01Sheridan County, MTMT3,436-721+15%

02Hill County, MTMT16,167-577−41%

03Blaine County, MTMT6,860-518−284%

04Silver Bow County, MTMT36,118-406−161%

05Teton County, MTMT6,496-372−314%

06Phillips County, MTMT4,203-348−38%

07Fergus County, MTMT11,825-307+62%

08Valley County, MTMT7,385-306−46%

09Pondera County, MTMT6,072-271+2911%

10Daniels County, MTMT1,612-266+7%

11Judith Basin County, MTMT2,162-257−647%

12McCone County, MTMT1,720-243−19%

13Carter County, MTMT1,383-200+40%

14Roosevelt County, MTMT10,242-195−49%

15Golden Valley County, MTMT844-158−222%

16Chouteau County, MTMT5,865-157−130%

17Powell County, MTMT7,157-153−127%

18Rosebud County, MTMT8,253-150−87%

19Treasure County, MTMT728-143+1000%

20Deer Lodge County, MTMT9,709-119−86%

21Powder River County, MTMT1,781-115−50%

22Dawson County, MTMT8,692-93−79%

23Wheatland County, MTMT2,100-91−800%

24Garfield County, MTMT1,148-73−76%

25Park County, MTMT18,214-58−105%

26Wibaux County, MTMT885-51−59%

27Meagher County, MTMT2,137-41−136%

28Prairie County, MTMT1,112-20−89%

29Petroleum County, MTMT548+1−104%

30Custer County, MTMT12,034+3−400%

31Musselshell County, MTMT5,582+41−90%

32Sweet Grass County, MTMT3,762+42−91%

33Beaverhead County, MTMT10,043+44−94%

34Fallon County, MTMT2,959+53−120%

35Toole County, MTMT5,211+57−74%

36Richland County, MTMT11,377+79−108%

37Glacier County, MTMT13,463+152−87%

38Liberty County, MTMT1,957+181−232%

39Big Horn County, MTMT12,752+194−85%

40Granite County, MTMT3,658+249−12%

41Mineral County, MTMT5,185+339−40%

42Carbon County, MTMT11,466+526−64%

43Madison County, MTMT10,026+840−3%

44Lincoln County, MTMT22,328+850−37%

45Stillwater County, MTMT9,445+922−44%

46Cascade County, MTMT85,029+970−64%

47Sanders County, MTMT14,062+1,186−24%

48Broadwater County, MTMT8,493+1,227+15%

49Jefferson County, MTMT13,329+1,357−36%

50Lake County, MTMT33,392+2,239−59%

51Ravalli County, MTMT48,582+4,142−63%

52Lewis and Clark County, MTMT75,331+7,679−7%

53Missoula County, MTMT123,513+13,497−21%

54Flathead County, MTMT115,429+16,457+8%

55Yellowstone County, MTMT172,692+18,620+17%

56Gallatin County, MTMT128,740+21,682+25%

SHOWING 1–56 OF 56

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