RANKING · 2010 CENSUS · 56 SHOWN OF 56

Most densely populated, Montana counties · 2010

Montana counties ranked by residents per square mile (2023). 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 Fastest shrinking Most sparsely populated Best broadband access Worst broadband access

YEAR1990 2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION DENSITYVS 2000

01Yellowstone County, MTMT172,69256+14%

02Silver Bow County, MTMT36,11848−1%

03Missoula County, MTMT123,51342+14%

04Gallatin County, MTMT128,74034+32%

05Cascade County, MTMT85,02930+1%

06Lake County, MTMT33,39219+8%

07Lewis and Clark County, MTMT75,33118+14%

08Flathead County, MTMT115,42918+22%

09Ravalli County, MTMT48,58217+11%

10Deer Lodge County, MTMT9,70913−1%

11Jefferson County, MTMT13,3297+14%

12Park County, MTMT18,2146−0%

13Hill County, MTMT16,1676−3%

14Lincoln County, MTMT22,3285+5%

15Stillwater County, MTMT9,4455+11%

16Carbon County, MTMT11,4665+6%

17Broadwater County, MTMT8,4935+28%

18Richland County, MTMT11,3775+1%

19Glacier County, MTMT13,4634+1%

20Roosevelt County, MTMT10,2424−2%

21Sanders County, MTMT14,0624+12%

22Pondera County, MTMT6,0724−4%

23Dawson County, MTMT8,6924−1%

24Mineral County, MTMT5,1853+9%

25Custer County, MTMT12,0343+0%

26Powell County, MTMT7,1573−2%

27Toole County, MTMT5,2113+1%

28Teton County, MTMT6,4963−6%

29Fergus County, MTMT11,8253−3%

30Big Horn County, MTMT12,7523+2%

31Musselshell County, MTMT5,5822+1%

32Madison County, MTMT10,0262+12%

33Sheridan County, MTMT3,4362−18%

34Sweet Grass County, MTMT3,7622+1%

35Rosebud County, MTMT8,2532−2%

36Fallon County, MTMT2,9592+2%

37Granite County, MTMT3,6582+9%

38Beaverhead County, MTMT10,0432+0%

39Liberty County, MTMT1,9572+8%

40Blaine County, MTMT6,8602−7%

41Wheatland County, MTMT2,1002−4%

42Valley County, MTMT7,3851−4%

43Chouteau County, MTMT5,8651−3%

44Daniels County, MTMT1,6121−13%

45Wibaux County, MTMT8851−5%

46Judith Basin County, MTMT2,1621−11%

47Phillips County, MTMT4,2031−8%

48Meagher County, MTMT2,1371−2%

49Golden Valley County, MTMT8441−15%

50Treasure County, MTMT7281−17%

51Prairie County, MTMT1,1121−2%

52McCone County, MTMT1,7201−12%

53Powder River County, MTMT1,7811−6%

54Carter County, MTMT1,3830−15%

55Petroleum County, MTMT5480+0%

56Garfield County, MTMT1,1480−6%

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