RANKING · 2010 CENSUS · 56 SHOWN OF 56

Most population gained, Montana counties · 2010

Montana counties that added 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

01Gallatin County, MTMT128,740+21,682+25%

02Yellowstone County, MTMT172,692+18,620+17%

03Flathead County, MTMT115,429+16,457+8%

04Missoula County, MTMT123,513+13,497−21%

05Lewis and Clark County, MTMT75,331+7,679−7%

06Ravalli County, MTMT48,582+4,142−63%

07Lake County, MTMT33,392+2,239−59%

08Jefferson County, MTMT13,329+1,357−36%

09Broadwater County, MTMT8,493+1,227+15%

10Sanders County, MTMT14,062+1,186−24%

11Cascade County, MTMT85,029+970−64%

12Stillwater County, MTMT9,445+922−44%

13Lincoln County, MTMT22,328+850−37%

14Madison County, MTMT10,026+840−3%

15Carbon County, MTMT11,466+526−64%

16Mineral County, MTMT5,185+339−40%

17Granite County, MTMT3,658+249−12%

18Big Horn County, MTMT12,752+194−85%

19Liberty County, MTMT1,957+181−232%

20Glacier County, MTMT13,463+152−87%

21Richland County, MTMT11,377+79−108%

22Toole County, MTMT5,211+57−74%

23Fallon County, MTMT2,959+53−120%

24Beaverhead County, MTMT10,043+44−94%

25Sweet Grass County, MTMT3,762+42−91%

26Musselshell County, MTMT5,582+41−90%

27Custer County, MTMT12,034+3−400%

28Petroleum County, MTMT548+1−104%

29Prairie County, MTMT1,112-20−89%

30Meagher County, MTMT2,137-41−136%

31Wibaux County, MTMT885-51−59%

32Park County, MTMT18,214-58−105%

33Garfield County, MTMT1,148-73−76%

34Wheatland County, MTMT2,100-91−800%

35Dawson County, MTMT8,692-93−79%

36Powder River County, MTMT1,781-115−50%

37Deer Lodge County, MTMT9,709-119−86%

38Treasure County, MTMT728-143+1000%

39Rosebud County, MTMT8,253-150−87%

40Powell County, MTMT7,157-153−127%

41Chouteau County, MTMT5,865-157−130%

42Golden Valley County, MTMT844-158−222%

43Roosevelt County, MTMT10,242-195−49%

44Carter County, MTMT1,383-200+40%

45McCone County, MTMT1,720-243−19%

46Judith Basin County, MTMT2,162-257−647%

47Daniels County, MTMT1,612-266+7%

48Pondera County, MTMT6,072-271+2911%

49Valley County, MTMT7,385-306−46%

50Fergus County, MTMT11,825-307+62%

51Phillips County, MTMT4,203-348−38%

52Teton County, MTMT6,496-372−314%

53Silver Bow County, MTMT36,118-406−161%

54Blaine County, MTMT6,860-518−284%

55Hill County, MTMT16,167-577−41%

56Sheridan County, MTMT3,436-721+15%

SHOWING 1–56 OF 56

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