RANKING · 1990 CENSUS · 44 SHOWN OF 44

Oldest by median age, Idaho counties · 1990

Idaho counties ranked by median age of residents (1990 ACS). This list covers the 44 counties in Idaho 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 –

01Lemhi County, IDID8,47438.1–

02Clearwater County, IDID9,11837.8–

03Valley County, IDID12,83137.2–

04Shoshone County, IDID14,13037.2–

05Washington County, IDID11,58337.0–

06Bonner County, IDID54,42036.8–

07Camas County, IDID1,31636.7–

08Idaho County, IDID17,87436.5–

09Lewis County, IDID3,70436.5–

10Adams County, IDID5,01336.1–

11Gem County, IDID21,77336.1–

12Boise County, IDID8,54535.8–

13Nez Perce County, IDID42,90535.5–

14Lincoln County, IDID5,60335.0–

15Kootenai County, IDID191,86435.0–

16Gooding County, IDID16,44634.9–

17Custer County, IDID4,63634.7–

18Benewah County, IDID10,50834.7–

19Payette County, IDID27,82434.3–

20Blaine County, IDID25,51733.4–

21Butte County, IDID2,78333.3–

22Twin Falls County, IDID97,53933.2–

23Boundary County, IDID13,99732.7–

24Clark County, IDID78332.7–

25Jerome County, IDID26,36232.7–

26Ada County, IDID546,14131.9–

27Canyon County, IDID275,12331.5–

28Bear Lake County, IDID6,72731.2–

29Oneida County, IDID5,08531.0–

30Owyhee County, IDID12,66130.8–

31Teton County, IDID13,25430.6–

32Caribou County, IDID7,25230.6–

33Minidoka County, IDID22,91130.3–

34Power County, IDID8,24630.0–

35Bannock County, IDID91,59129.7–

36Cassia County, IDID26,39729.0–

37Bonneville County, IDID135,77128.8–

38Fremont County, IDID14,20828.3–

39Bingham County, IDID51,15328.1–

40Elmore County, IDID29,46527.9–

41Franklin County, IDID15,88927.8–

42Latah County, IDID41,84227.5–

43Jefferson County, IDID35,29726.4–

44Madison County, IDID55,17220.0–

SHOWING 1–44 OF 44

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