RANKING · 2010 CENSUS · 44 SHOWN OF 44

Oldest by median age, Idaho counties · 2010

Idaho counties ranked by median age of residents (2010 ACS). This list covers the 44 counties in Idaho that qualify, ranked against each other statewide. The median across all 44 is 37.7.

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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

01Adams County, IDID5,01350.0+13%

02Lemhi County, IDID8,47449.7+16%

03Clearwater County, IDID9,11849.0+18%

04Boise County, IDID8,54548.4+20%

05Custer County, IDID4,63648.0+17%

06Idaho County, IDID17,87448.0+13%

07Lewis County, IDID3,70448.0+13%

08Valley County, IDID12,83146.9+8%

09Shoshone County, IDID14,13046.2+11%

10Bonner County, IDID54,42045.8+12%

11Benewah County, IDID10,50844.8+14%

12Camas County, IDID1,31644.3+12%

13Washington County, IDID11,58343.6+11%

14Gem County, IDID21,77342.9+14%

15Boundary County, IDID13,99742.8+12%

16Butte County, IDID2,78341.7+7%

17Nez Perce County, IDID42,90540.8+7%

18Bear Lake County, IDID6,72740.5+13%

19Blaine County, IDID25,51740.4+8%

20Oneida County, IDID5,08539.1+9%

21Kootenai County, IDID191,86438.9+8%

22Caribou County, IDID7,25237.7+8%

23Payette County, IDID27,82437.2+8%

24Owyhee County, IDID12,66136.0+9%

25Minidoka County, IDID22,91135.3+5%

26Ada County, IDID546,14134.8+6%

27Twin Falls County, IDID97,53934.4−1%

28Gooding County, IDID16,44634.3−2%

29Fremont County, IDID14,20833.5+5%

30Power County, IDID8,24633.2+5%

31Teton County, IDID13,25433.2+6%

32Clark County, IDID78332.7+7%

33Cassia County, IDID26,39732.0+3%

34Lincoln County, IDID5,60332.0−7%

35Bingham County, IDID51,15331.8+7%

36Bonneville County, IDID135,77131.70%

37Jerome County, IDID26,36231.7−4%

38Canyon County, IDID275,12331.6+4%

39Franklin County, IDID15,88931.5+14%

40Bannock County, IDID91,59131.4+5%

41Elmore County, IDID29,46530.0+3%

42Jefferson County, IDID35,29730.0+4%

43Latah County, IDID41,84228.3+1%

44Madison County, IDID55,17222.6+9%

SHOWING 1–44 OF 44

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