RANKING · 2024 ACS · 44 SHOWN OF 44

Oldest by median age, Idaho counties

Idaho counties ranked by median age of residents (2024 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 2000

01Custer County, IDID4,63660.0+46%

02Adams County, IDID5,01353.9+21%

03Boise County, IDID8,54553.4+32%

04Lemhi County, IDID8,47453.3+25%

05Clearwater County, IDID9,11852.2+25%

06Idaho County, IDID17,87449.4+17%

07Lewis County, IDID3,70449.0+15%

08Bonner County, IDID54,42048.1+18%

09Valley County, IDID12,83146.9+8%

10Blaine County, IDID25,51745.6+22%

11Benewah County, IDID10,50845.5+16%

12Washington County, IDID11,58345.0+15%

13Shoshone County, IDID14,13044.8+7%

14Gem County, IDID21,77344.2+18%

15Boundary County, IDID13,99743.7+14%

16Butte County, IDID2,78341.3+6%

17Nez Perce County, IDID42,90541.2+8%

18Kootenai County, IDID191,86440.9+13%

19Oneida County, IDID5,08540.8+13%

20Bear Lake County, IDID6,72740.5+13%

21Fremont County, IDID14,20840.0+25%

22Teton County, IDID13,25439.6+27%

23Owyhee County, IDID12,66139.0+19%

24Payette County, IDID27,82438.9+13%

25Caribou County, IDID7,25238.5+10%

26Ada County, IDID546,14138.4+17%

27Gooding County, IDID16,44638.1+9%

28Lincoln County, IDID5,60337.2+8%

29Camas County, IDID1,31636.8−7%

30Twin Falls County, IDID97,53936.1+3%

31Bannock County, IDID91,59135.2+18%

32Bingham County, IDID51,15335.0+18%

33Canyon County, IDID275,12334.9+14%

34Minidoka County, IDID22,91134.9+4%

35Power County, IDID8,24634.6+9%

36Jerome County, IDID26,36234.0+3%

37Bonneville County, IDID135,77133.6+6%

38Franklin County, IDID15,88933.3+20%

39Cassia County, IDID26,39733.2+7%

40Elmore County, IDID29,46533.1+14%

41Jefferson County, IDID35,29732.8+14%

42Clark County, IDID78331.1+1%

43Latah County, IDID41,84230.6+10%

44Madison County, IDID55,17221.4+3%

SHOWING 1–44 OF 44

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES