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.

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 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, IDID135,77131.7−0%

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

Download CSV (full list, 44 rows)

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