RANKING · 1990 CENSUS · 56 SHOWN OF 56

Youngest by median age, Montana counties · 1990

Montana counties with the youngest median age (1990 ACS). This list covers the 56 counties in Montana that qualify, ranked against each other statewide. The median across all 56 is 36.0.

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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 –

01Big Horn County, MTMT12,75228.1–

02Glacier County, MTMT13,46328.8–

03Rosebud County, MTMT8,25329.6–

04Gallatin County, MTMT128,74029.9–

05Roosevelt County, MTMT10,24230.1–

06Blaine County, MTMT6,86031.6–

07Missoula County, MTMT123,51331.7–

08Beaverhead County, MTMT10,04331.9–

09Hill County, MTMT16,16732.0–

10Cascade County, MTMT85,02932.8–

11Richland County, MTMT11,37733.2–

12Yellowstone County, MTMT172,69233.5–

13Pondera County, MTMT6,07234.0–

14Lewis and Clark County, MTMT75,33134.0–

15Phillips County, MTMT4,20334.0–

16Liberty County, MTMT1,95734.1–

17Lake County, MTMT33,39234.7–

18Jefferson County, MTMT13,32935.1–

19Fallon County, MTMT2,95935.2–

20Flathead County, MTMT115,42935.3–

21Lincoln County, MTMT22,32835.3–

22Toole County, MTMT5,21135.3–

23Custer County, MTMT12,03435.4–

24Garfield County, MTMT1,14835.6–

25Dawson County, MTMT8,69235.6–

26Petroleum County, MTMT54835.8–

27McCone County, MTMT1,72035.9–

28Mineral County, MTMT5,18535.9–

29Silver Bow County, MTMT36,11836.0–

30Treasure County, MTMT72836.3–

31Powell County, MTMT7,15736.4–

32Teton County, MTMT6,49636.4–

33Broadwater County, MTMT8,49336.6–

34Stillwater County, MTMT9,44536.6–

35Sanders County, MTMT14,06236.7–

36Chouteau County, MTMT5,86536.7–

37Valley County, MTMT7,38536.7–

38Powder River County, MTMT1,78136.7–

39Golden Valley County, MTMT84436.9–

40Park County, MTMT18,21437.0–

41Wibaux County, MTMT88537.0–

42Fergus County, MTMT11,82537.6–

43Meagher County, MTMT2,13737.6–

44Carter County, MTMT1,38337.8–

45Ravalli County, MTMT48,58237.8–

46Madison County, MTMT10,02637.8–

47Deer Lodge County, MTMT9,70938.2–

48Wheatland County, MTMT2,10038.6–

49Judith Basin County, MTMT2,16238.6–

50Carbon County, MTMT11,46639.1–

51Granite County, MTMT3,65839.3–

52Musselshell County, MTMT5,58239.4–

53Sweet Grass County, MTMT3,76239.5–

54Sheridan County, MTMT3,43639.6–

55Daniels County, MTMT1,61241.3–

56Prairie County, MTMT1,11243.3–

SHOWING 1–56 OF 56

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