RANKING · 2025 ESTIMATES · 56 SHOWN OF 56

Most densely populated, Montana counties

Montana counties ranked by residents per square mile (2025). 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, MTMT172,69266+34%

02Silver Bow County, MTMT36,11850+4%

03Gallatin County, MTMT128,74049+90%

04Missoula County, MTMT123,51348+29%

05Cascade County, MTMT85,02932+6%

06▲2Flathead County, MTMT115,42923+55%

07▼1Lake County, MTMT33,39222+26%

08▼1Lewis and Clark County, MTMT75,33122+35%

09Ravalli County, MTMT48,58220+35%

10Deer Lodge County, MTMT9,70913+3%

11Jefferson County, MTMT13,3298+33%

12▲1Broadwater County, MTMT8,4937+94%

13▼1Park County, MTMT18,2146+16%

14▲2Lincoln County, MTMT22,3286+19%

15▲2Carbon County, MTMT11,4666+20%

16▼2Hill County, MTMT16,1676−3%

17▼2Richland County, MTMT11,3775+18%

18Stillwater County, MTMT9,4455+15%

19▲2Sanders County, MTMT14,0625+37%

20▼1Glacier County, MTMT13,4634+2%

21▼1Roosevelt County, MTMT10,2424−4%

22▲1Mineral County, MTMT5,1854+33%

23▲1Pondera County, MTMT6,0724−5%

24▼2Dawson County, MTMT8,6924−4%

25Custer County, MTMT12,0343+3%

26Powell County, MTMT7,15730%

27▲4Musselshell County, MTMT5,5823+24%

28▼1Teton County, MTMT6,4963+1%

29▲3Madison County, MTMT10,0263+46%

30▼2Fergus County, MTMT11,8253−1%

31▼1Toole County, MTMT5,2113−1%

32▼3Big Horn County, MTMT12,7523+1%

33▲2Granite County, MTMT3,6582+29%

34▼1Sheridan County, MTMT3,4362−16%

35▼1Sweet Grass County, MTMT3,7622+4%

36Fallon County, MTMT2,9592+4%

37Beaverhead County, MTMT10,0432+9%

38▲1Rosebud County, MTMT8,2532−12%

39▼1Blaine County, MTMT6,8602−2%

40Valley County, MTMT7,3851−4%

41Chouteau County, MTMT5,8651−2%

42Wheatland County, MTMT2,1001−7%

43Liberty County, MTMT1,9571−9%

44▲1Judith Basin County, MTMT2,1621−7%

45▼1Daniels County, MTMT1,6121−20%

46Wibaux County, MTMT8851−17%

47▲1Meagher County, MTMT2,1371+11%

48▼1Phillips County, MTMT4,2031−9%

49Treasure County, MTMT7281−15%

50Golden Valley County, MTMT8441−19%

51McCone County, MTMT1,7201−13%

52Prairie County, MTMT1,1121−7%

53Powder River County, MTMT1,7811−4%

54Carter County, MTMT1,3830+2%

55Petroleum County, MTMT5480+11%

56Garfield County, MTMT1,1480−10%

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UPDATED 2026-09-11 · DATA: US CENSUS BUREAU POPULATION ESTIMATES