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. The median across all 44 is 35.1.

Flip the list · Youngest by median age, US counties →

IdahoAll states All rankings

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, IDID27,82434.40%

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, IDID91,59129.80%

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, IDID15,88927.70%

44Madison County, IDID55,17220.7+4%

SHOWING 1–44 OF 44

Download CSV (full list, 44 rows)

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