RANKING · 1990 CENSUS · 56 SHOWN OF 56

Oldest by median age, Montana counties · 1990

Montana counties ranked by median age of residents (2023 ACS). This list covers the 56 counties in Montana that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros ZIP codes

RELATEDYoungest by median age Most foreign-born residents Highest uninsured rate Most women Most men Highest disability rate

YEAR1990 2000 2010 2020 2024

RANKPLACESTATEPOPMEDIAN AGEVS 2000

01Prairie County, MTMT1,11243.3−11%

02Daniels County, MTMT1,61241.3−12%

03Sheridan County, MTMT3,43639.6−12%

04Sweet Grass County, MTMT3,76239.5−4%

05Musselshell County, MTMT5,58239.4−9%

06Granite County, MTMT3,65839.3−8%

07Carbon County, MTMT11,46639.1−7%

08Judith Basin County, MTMT2,16238.6−8%

09Wheatland County, MTMT2,10038.6−7%

10Deer Lodge County, MTMT9,70938.2−10%

11Madison County, MTMT10,02637.8−13%

12Ravalli County, MTMT48,58237.8−8%

13Carter County, MTMT1,38337.8−10%

14Meagher County, MTMT2,13737.6−12%

15Fergus County, MTMT11,82537.6−11%

16Wibaux County, MTMT88537.0−13%

17Park County, MTMT18,21437.0−9%

18Golden Valley County, MTMT84436.9−11%

19Powder River County, MTMT1,78136.7−13%

20Valley County, MTMT7,38536.7−12%

21Chouteau County, MTMT5,86536.7−7%

22Sanders County, MTMT14,06236.7−17%

23Stillwater County, MTMT9,44536.6−10%

24Broadwater County, MTMT8,49336.6−11%

25Teton County, MTMT6,49636.4−9%

26Powell County, MTMT7,15736.4−8%

27Treasure County, MTMT72836.3−13%

28Silver Bow County, MTMT36,11836.0−8%

29Mineral County, MTMT5,18535.9−13%

30McCone County, MTMT1,72035.9−15%

31Petroleum County, MTMT54835.8−13%

32Dawson County, MTMT8,69235.6−13%

33Garfield County, MTMT1,14835.6−15%

34Custer County, MTMT12,03435.4−10%

35Toole County, MTMT5,21135.3−10%

36Lincoln County, MTMT22,32835.3−16%

37Flathead County, MTMT115,42935.3−10%

38Fallon County, MTMT2,95935.2−14%

39Jefferson County, MTMT13,32935.1−13%

40Lake County, MTMT33,39234.7−9%

41Liberty County, MTMT1,95734.1−18%

42Phillips County, MTMT4,20334.0−17%

43Lewis and Clark County, MTMT75,33134.0−11%

44Pondera County, MTMT6,07234.0−12%

45Yellowstone County, MTMT172,69233.5−9%

46Richland County, MTMT11,37733.2−15%

47Cascade County, MTMT85,02932.8−11%

48Hill County, MTMT16,16732.0−7%

49Beaverhead County, MTMT10,04331.9−15%

50Missoula County, MTMT123,51331.7−5%

51Blaine County, MTMT6,86031.6−8%

52Roosevelt County, MTMT10,24230.1−7%

53Gallatin County, MTMT128,74029.9−3%

54Rosebud County, MTMT8,25329.6−14%

55Glacier County, MTMT13,46328.8−6%

56Big Horn County, MTMT12,75228.1−6%

SHOWING 1–56 OF 56

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