RANKING · 2020 CENSUS · 56 SHOWN OF 56

Oldest by median age, Montana counties · 2020

Montana counties ranked by median age of residents (2020 ACS). This list covers the 56 counties in Montana that qualify, ranked against each other statewide. The median across all 56 is 45.1.

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SAME RANKING BYCities States Metros ZIP codes

RELATEDLargest foreign-born population Most residents with a disability Largest veteran population Most uninsured people Largest senior population Most unmarried people

YEAR1990 2000 2010 2020 2024

RANKPLACESTATEPOPMEDIAN AGEVS 2000

01Sanders County, MTMT14,06255.2+25%

02Lincoln County, MTMT22,32854.0+28%

03Petroleum County, MTMT54853.4+30%

04Meagher County, MTMT2,13753.2+24%

05Golden Valley County, MTMT84453.1+28%

06Madison County, MTMT10,02652.9+22%

07Mineral County, MTMT5,18552.8+28%

08Prairie County, MTMT1,11252.8+8%

09Granite County, MTMT3,65852.6+23%

10Judith Basin County, MTMT2,16251.4+22%

11Musselshell County, MTMT5,58251.3+19%

12Powder River County, MTMT1,78150.8+21%

13Ravalli County, MTMT48,58250.2+22%

14Carbon County, MTMT11,46650.0+19%

15Deer Lodge County, MTMT9,70949.4+17%

16Jefferson County, MTMT13,32949.2+22%

17Stillwater County, MTMT9,44548.6+19%

18Sweet Grass County, MTMT3,76248.4+17%

19Wibaux County, MTMT88547.8+13%

20Fergus County, MTMT11,82547.5+12%

21Wheatland County, MTMT2,10047.2+14%

22Park County, MTMT18,21446.9+16%

23McCone County, MTMT1,72046.2+9%

24Sheridan County, MTMT3,43646.0+2%

25Powell County, MTMT7,15745.9+16%

26Daniels County, MTMT1,61245.8−3%

27Broadwater County, MTMT8,49345.7+11%

28Teton County, MTMT6,49645.1+13%

29Treasure County, MTMT72845.0+8%

30Garfield County, MTMT1,14844.9+8%

31Lake County, MTMT33,39244.7+17%

32Phillips County, MTMT4,20344.7+10%

33Valley County, MTMT7,38544.1+6%

34Beaverhead County, MTMT10,04343.9+17%

35Carter County, MTMT1,38343.1+3%

36Flathead County, MTMT115,42942.9+10%

37Pondera County, MTMT6,07242.1+9%

38Liberty County, MTMT1,95742.1+1%

39Silver Bow County, MTMT36,11841.8+7%

40Dawson County, MTMT8,69241.3+1%

41Lewis and Clark County, MTMT75,33141.3+9%

42Custer County, MTMT12,03441.0+4%

43Toole County, MTMT5,21141.0+5%

44Chouteau County, MTMT5,86540.3+3%

45Rosebud County, MTMT8,25339.3+14%

46Fallon County, MTMT2,95939.0−5%

47Cascade County, MTMT85,02938.9+6%

48Yellowstone County, MTMT172,69238.8+5%

49Richland County, MTMT11,37738.4−2%

50Missoula County, MTMT123,51337.7+14%

51Hill County, MTMT16,16735.3+2%

52Blaine County, MTMT6,86034.50%

53Gallatin County, MTMT128,74033.4+9%

54Roosevelt County, MTMT10,24233.2+3%

55Glacier County, MTMT13,46332.8+7%

56Big Horn County, MTMT12,75231.5+6%

SHOWING 1–56 OF 56

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