RANKING · 1990 CENSUS · 56 SHOWN OF 56

Oldest by median age, Montana counties · 1990

Montana counties ranked by median age of residents (1990 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

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 –

01Prairie County, MTMT1,11243.3–

02Daniels County, MTMT1,61241.3–

03Sheridan County, MTMT3,43639.6–

04Sweet Grass County, MTMT3,76239.5–

05Musselshell County, MTMT5,58239.4–

06Granite County, MTMT3,65839.3–

07Carbon County, MTMT11,46639.1–

08Judith Basin County, MTMT2,16238.6–

09Wheatland County, MTMT2,10038.6–

10Deer Lodge County, MTMT9,70938.2–

11Madison County, MTMT10,02637.8–

12Ravalli County, MTMT48,58237.8–

13Carter County, MTMT1,38337.8–

14Meagher County, MTMT2,13737.6–

15Fergus County, MTMT11,82537.6–

16Wibaux County, MTMT88537.0–

17Park County, MTMT18,21437.0–

18Golden Valley County, MTMT84436.9–

19Powder River County, MTMT1,78136.7–

20Valley County, MTMT7,38536.7–

21Chouteau County, MTMT5,86536.7–

22Sanders County, MTMT14,06236.7–

23Stillwater County, MTMT9,44536.6–

24Broadwater County, MTMT8,49336.6–

25Teton County, MTMT6,49636.4–

26Powell County, MTMT7,15736.4–

27Treasure County, MTMT72836.3–

28Silver Bow County, MTMT36,11836.0–

29Mineral County, MTMT5,18535.9–

30McCone County, MTMT1,72035.9–

31Petroleum County, MTMT54835.8–

32Dawson County, MTMT8,69235.6–

33Garfield County, MTMT1,14835.6–

34Custer County, MTMT12,03435.4–

35Toole County, MTMT5,21135.3–

36Lincoln County, MTMT22,32835.3–

37Flathead County, MTMT115,42935.3–

38Fallon County, MTMT2,95935.2–

39Jefferson County, MTMT13,32935.1–

40Lake County, MTMT33,39234.7–

41Liberty County, MTMT1,95734.1–

42Phillips County, MTMT4,20334.0–

43Lewis and Clark County, MTMT75,33134.0–

44Pondera County, MTMT6,07234.0–

45Yellowstone County, MTMT172,69233.5–

46Richland County, MTMT11,37733.2–

47Cascade County, MTMT85,02932.8–

48Hill County, MTMT16,16732.0–

49Beaverhead County, MTMT10,04331.9–

50Missoula County, MTMT123,51331.7–

51Blaine County, MTMT6,86031.6–

52Roosevelt County, MTMT10,24230.1–

53Gallatin County, MTMT128,74029.9–

54Rosebud County, MTMT8,25329.6–

55Glacier County, MTMT13,46328.8–

56Big Horn County, MTMT12,75228.1–

SHOWING 1–56 OF 56

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU DECENNIAL CENSUS