RANKING · 2020 CENSUS · 44 SHOWN OF 44

Youngest by median age, Idaho counties · 2020

Idaho counties with the youngest median age (2020 ACS). This list covers the 44 counties in Idaho that qualify, ranked against each other statewide. The median across all 44 is 39.4.

Flip the list · Oldest 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

01Madison County, IDID55,17223.1+12%

02Latah County, IDID41,84231.0+11%

03Jefferson County, IDID35,29732.1+11%

04Elmore County, IDID29,46532.7+12%

05Bonneville County, IDID135,77133.1+4%

06Cassia County, IDID26,39733.1+6%

07Jerome County, IDID26,36233.4+2%

08Franklin County, IDID15,88933.9+22%

09Canyon County, IDID275,12334.5+13%

10Bannock County, IDID91,59134.7+16%

11Bingham County, IDID51,15334.8+17%

12Minidoka County, IDID22,91135.2+5%

13Power County, IDID8,24635.3+12%

14Twin Falls County, IDID97,53935.8+3%

15Lincoln County, IDID5,60336.5+6%

16Gooding County, IDID16,44637.1+6%

17Ada County, IDID546,14137.4+14%

18Caribou County, IDID7,25237.5+7%

19Fremont County, IDID14,20837.7+18%

20Teton County, IDID13,25437.7+20%

21Clark County, IDID78337.9+23%

22Owyhee County, IDID12,66138.8+18%

23Payette County, IDID27,82439.4+15%

24Bear Lake County, IDID6,72740.1+12%

25Oneida County, IDID5,08540.3+12%

26Nez Perce County, IDID42,90540.9+7%

27Kootenai County, IDID191,86441.2+14%

28Butte County, IDID2,78342.7+10%

29Gem County, IDID21,77344.1+18%

30Blaine County, IDID25,51745.4+21%

31Washington County, IDID11,58346.0+17%

32Boundary County, IDID13,99746.9+22%

33Camas County, IDID1,31647.0+18%

34Benewah County, IDID10,50847.5+21%

35Shoshone County, IDID14,13048.2+15%

36Lewis County, IDID3,70448.8+15%

37Bonner County, IDID54,42049.3+21%

38Valley County, IDID12,83149.5+14%

39Idaho County, IDID17,87451.4+22%

40Clearwater County, IDID9,11852.1+25%

41Lemhi County, IDID8,47452.6+23%

42Boise County, IDID8,54553.9+33%

43Custer County, IDID4,63654.0+31%

44Adams County, IDID5,01354.9+24%

SHOWING 1–44 OF 44

Download CSV (full list, 44 rows)

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