RANKING · 2000 CENSUS · 44 SHOWN OF 44

Oldest by median age, Idaho counties · 2000

Idaho counties ranked by median age of residents (2000 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 1990

01Adams County, IDID5,01344.4+23%

02Valley County, IDID12,83143.5+17%

03Lemhi County, IDID8,47442.7+12%

04Lewis County, IDID3,70442.5+17%

05Idaho County, IDID17,87442.3+16%

06Shoshone County, IDID14,13041.8+12%

07Clearwater County, IDID9,11841.7+10%

08Custer County, IDID4,63641.2+19%

09Bonner County, IDID54,42040.8+11%

10Boise County, IDID8,54540.4+13%

11Camas County, IDID1,31639.7+8%

12Benewah County, IDID10,50839.2+13%

13Washington County, IDID11,58339.2+6%

14Butte County, IDID2,78338.8+17%

15Boundary County, IDID13,99738.3+17%

16Nez Perce County, IDID42,90538.1+7%

17Gem County, IDID21,77337.5+4%

18Blaine County, IDID25,51737.4+12%

19Kootenai County, IDID191,86436.1+3%

20Oneida County, IDID5,08536.0+16%

21Bear Lake County, IDID6,72735.8+15%

22Gooding County, IDID16,44635.1+1%

23Caribou County, IDID7,25235.0+14%

24Twin Falls County, IDID97,53934.9+5%

25Payette County, IDID27,82434.4+0%

26Lincoln County, IDID5,60334.3−2%

27Minidoka County, IDID22,91133.5+11%

28Jerome County, IDID26,36232.9+1%

29Owyhee County, IDID12,66132.9+7%

30Ada County, IDID546,14132.8+3%

31Fremont County, IDID14,20831.9+13%

32Bonneville County, IDID135,77131.8+10%

33Power County, IDID8,24631.6+5%

34Teton County, IDID13,25431.3+2%

35Cassia County, IDID26,39731.1+7%

36Clark County, IDID78330.7−6%

37Canyon County, IDID275,12330.5−3%

38Bannock County, IDID91,59129.8+0%

39Bingham County, IDID51,15329.7+6%

40Elmore County, IDID29,46529.1+4%

41Jefferson County, IDID35,29728.8+9%

42Latah County, IDID41,84227.9+2%

43Franklin County, IDID15,88927.7−0%

44Madison County, IDID55,17220.7+4%

SHOWING 1–44 OF 44

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