RANKING · 2020 CENSUS · 56 SHOWN OF 56

Most densely populated, Montana counties · 2020

Montana counties ranked by residents per square mile (2020). This list covers the 56 counties in Montana that qualify, ranked against each other statewide. The median across all 56 is 3.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest growing Fastest shrinking Most population gained Most population lost Most sparsely populated

YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01Yellowstone County, MTMT172,69263+27%

02Silver Bow County, MTMT36,11849+2%

03Gallatin County, MTMT128,74046+75%

04Missoula County, MTMT123,51345+23%

05Cascade County, MTMT85,02931+5%

06Lake County, MTMT33,39221+17%

07Lewis and Clark County, MTMT75,33121+27%

08Flathead County, MTMT115,42921+40%

09Ravalli County, MTMT48,58218+22%

10Deer Lodge County, MTMT9,709130%

11Jefferson County, MTMT13,3297+20%

12Park County, MTMT18,2146+10%

13Broadwater County, MTMT8,4936+54%

14Hill County, MTMT16,1676−2%

15Richland County, MTMT11,3776+19%

16Lincoln County, MTMT22,3285+4%

17Carbon County, MTMT11,4665+10%

18Stillwater County, MTMT9,4455+9%

19Glacier County, MTMT13,4635+4%

20Roosevelt County, MTMT10,2425+2%

21Sanders County, MTMT14,0624+21%

22Dawson County, MTMT8,6924−1%

23Mineral County, MTMT5,1854+17%

24Pondera County, MTMT6,0724−8%

25Custer County, MTMT12,0343+1%

26Powell County, MTMT7,1573−3%

27Teton County, MTMT6,4963−3%

28Fergus County, MTMT11,8253−4%

29Big Horn County, MTMT12,7523+4%

30Toole County, MTMT5,2113−6%

31Musselshell County, MTMT5,5823+5%

32Madison County, MTMT10,0262+26%

33Sheridan County, MTMT3,4362−14%

34Sweet Grass County, MTMT3,7622+2%

35Granite County, MTMT3,6582+17%

36Fallon County, MTMT2,9592+7%

37Beaverhead County, MTMT10,0432+2%

38Blaine County, MTMT6,86020%

39Rosebud County, MTMT8,2532−11%

40Valley County, MTMT7,3852−1%

41Chouteau County, MTMT5,8651−1%

42Wheatland County, MTMT2,1001−8%

43Liberty County, MTMT1,9571−9%

44Daniels County, MTMT1,6121−18%

45Judith Basin County, MTMT2,1621−13%

46Wibaux County, MTMT8851−12%

47Phillips County, MTMT4,2031−8%

48Meagher County, MTMT2,13710%

49Treasure County, MTMT7281−11%

50Golden Valley County, MTMT8441−21%

51McCone County, MTMT1,7201−13%

52Prairie County, MTMT1,1121−9%

53Powder River County, MTMT1,7811−9%

54Carter County, MTMT1,3830+4%

55Petroleum County, MTMT5480+1%

56Garfield County, MTMT1,1480−8%

SHOWING 1–56 OF 56

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UPDATED 2026-09-11 · DATA: US CENSUS BUREAU DECENNIAL CENSUS