RANKING · 1990 CENSUS · 56 SHOWN OF 56

Most densely populated, Montana counties · 1990

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

01Silver Bow County, MTMT36,11847−2%

02Yellowstone County, MTMT172,69243−12%

03Missoula County, MTMT123,51330−18%

04Cascade County, MTMT85,02929−3%

05Gallatin County, MTMT128,74019−26%

06Lake County, MTMT33,39214−21%

07Deer Lodge County, MTMT9,70914+9%

08Lewis and Clark County, MTMT75,33114−15%

09Flathead County, MTMT115,42912−20%

10Ravalli County, MTMT48,58210−31%

11Hill County, MTMT16,1676+6%

12Park County, MTMT18,2145−7%

13Richland County, MTMT11,3775+11%

14Lincoln County, MTMT22,3285−7%

15Jefferson County, MTMT13,3295−21%

16Roosevelt County, MTMT10,2425+4%

17Glacier County, MTMT13,4634−9%

18Dawson County, MTMT8,6924+5%

19Pondera County, MTMT6,0724+0%

20Carbon County, MTMT11,4664−15%

21Stillwater County, MTMT9,4454−20%

22Sanders County, MTMT14,0623−15%

23Custer County, MTMT12,0343+0%

24Powell County, MTMT7,1573−8%

25Sheridan County, MTMT3,4363+15%

26Fergus County, MTMT11,8253+2%

27Broadwater County, MTMT8,4933−24%

28Teton County, MTMT6,4963−3%

29Mineral County, MTMT5,1853−15%

30Toole County, MTMT5,2113−4%

31Big Horn County, MTMT12,7522−11%

32Musselshell County, MTMT5,5822−9%

33Rosebud County, MTMT8,2532+12%

34Fallon County, MTMT2,9592+9%

35Sweet Grass County, MTMT3,7622−13%

36Valley County, MTMT7,3852+7%

37Madison County, MTMT10,0262−13%

38Liberty County, MTMT1,9572+6%

39Blaine County, MTMT6,8602−4%

40Daniels County, MTMT1,6122+12%

41Wheatland County, MTMT2,1002−1%

42Beaverhead County, MTMT10,0432−8%

43Granite County, MTMT3,6581−10%

44Chouteau County, MTMT5,8651−9%

45Wibaux County, MTMT8851+12%

46Judith Basin County, MTMT2,1621−2%

47Phillips County, MTMT4,2031+12%

48Treasure County, MTMT7281+2%

49McCone County, MTMT1,7201+15%

50Prairie County, MTMT1,1121+15%

51Golden Valley County, MTMT8441−12%

52Meagher County, MTMT2,1371−6%

53Powder River County, MTMT1,7811+12%

54Carter County, MTMT1,3830+11%

55Garfield County, MTMT1,1480+24%

56Petroleum County, MTMT5480+5%

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