RANKING · 2024 ACS · 44 SHOWN OF 44

Youngest by median age, Idaho counties

Idaho counties with the youngest median age (2024 ACS). This list covers the 44 counties in Idaho that qualify, ranked against each other statewide. The median across all 44 is 39.6. Biggest climber in the top 100 since 2020: Clark County, ID, up 18 places to #3.

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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

01Madison County, IDID55,17221.4+3%

02Latah County, IDID41,84230.6+10%

03▲18Clark County, IDID78331.1+1%

04▼1Jefferson County, IDID35,29732.8+14%

05▼1Elmore County, IDID29,46533.1+14%

06Cassia County, IDID26,39733.2+7%

07▲1Franklin County, IDID15,88933.3+20%

08▼3Bonneville County, IDID135,77133.6+6%

09▼2Jerome County, IDID26,36234.0+3%

10▲3Power County, IDID8,24634.6+9%

11▼2Canyon County, IDID275,12334.9+14%

12Minidoka County, IDID22,91134.9+4%

13▼2Bingham County, IDID51,15335.0+18%

14▼4Bannock County, IDID91,59135.2+18%

15▼1Twin Falls County, IDID97,53936.1+3%

16▲17Camas County, IDID1,31636.8−7%

17▼2Lincoln County, IDID5,60337.2+8%

18▼2Gooding County, IDID16,44638.1+9%

19▼2Ada County, IDID546,14138.4+17%

20▼2Caribou County, IDID7,25238.5+10%

21▲2Payette County, IDID27,82438.9+13%

22Owyhee County, IDID12,66139.0+19%

23▼3Teton County, IDID13,25439.6+27%

24▼5Fremont County, IDID14,20840.0+25%

25▼1Bear Lake County, IDID6,72740.5+13%

26▼1Oneida County, IDID5,08540.8+13%

27Kootenai County, IDID191,86440.9+13%

28▼2Nez Perce County, IDID42,90541.2+8%

29▼1Butte County, IDID2,78341.3+6%

30▲2Boundary County, IDID13,99743.7+14%

31▼2Gem County, IDID21,77344.2+18%

32▲3Shoshone County, IDID14,13044.8+7%

33▼2Washington County, IDID11,58345.0+15%

34Benewah County, IDID10,50845.5+16%

35▼5Blaine County, IDID25,51745.6+22%

36▲2Valley County, IDID12,83146.9+8%

37Bonner County, IDID54,42048.1+18%

38▼2Lewis County, IDID3,70449.0+15%

39Idaho County, IDID17,87449.4+17%

40Clearwater County, IDID9,11852.2+25%

41Lemhi County, IDID8,47453.3+25%

42Boise County, IDID8,54553.4+32%

43▲1Adams County, IDID5,01353.9+21%

44▼1Custer County, IDID4,63660.0+46%

SHOWING 1–44 OF 44

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UPDATED 2026-09-11 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES