RANKING · 2020 CENSUS · 44 SHOWN OF 44

Fastest growing, Idaho counties · 2020

Idaho counties ranked by population growth from the 2010 census to 2020. This list covers the 44 counties in Idaho that qualify, ranked against each other statewide.

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SAME RANKING BYCities States Metros

RELATEDLargest by population Fastest shrinking Most population gained Most population lost Most densely populated Most sparsely populated

YEAR2000 2010 2020 2025

RANKPLACESTATEPOPPOPULATION GROWTHVS 2000

01Madison County, IDID55,172+41.0%+156%

02Ada County, IDID546,141+26.1%−43%

03Kootenai County, IDID191,864+23.7%−57%

04Canyon County, IDID275,123+22.3%−51%

05Valley County, IDID12,831+19.1%−24%

06Bonneville County, IDID135,771+18.9%+33%

07Jefferson County, IDID35,297+18.2%+15%

08Twin Falls County, IDID97,539+16.6%−17%

09Bonner County, IDID54,420+15.2%−60%

10Gem County, IDID21,773+14.4%−49%

11Teton County, IDID13,254+14.4%−81%

12Blaine County, IDID25,517+13.5%−66%

13Payette County, IDID27,824+12.2%−52%

14Franklin County, IDID15,889+11.0%−52%

15Adams County, IDID5,013+10.1%+49%

16Boundary County, IDID13,997+9.9%−47%

17Jerome County, IDID26,362+8.3%−61%

18Boise County, IDID8,545+8.3%−91%

19Minidoka County, IDID22,911+7.7%+83%

20Cassia County, IDID26,397+7.4%−23%

21Nez Perce County, IDID42,905+7.2%−34%

22Oneida County, IDID5,085+6.5%−64%

23Bear Lake County, IDID6,727+6.4%+20%

24Latah County, IDID41,842+6.1%−57%

25Elmore County, IDID29,465+6.0%−84%

26Bingham County, IDID51,153+5.2%−53%

27Bannock County, IDID91,591+5.0%−65%

28Owyhee County, IDID12,661+3.4%−87%

29Shoshone County, IDID14,130+3.2%−376%

30Washington County, IDID11,583+3.0%−82%

31Benewah County, IDID10,508+2.6%−83%

32Idaho County, IDID17,874+1.7%−87%

33Fremont County, IDID14,208+1.1%−86%

34Caribou County, IDID7,252+0.9%−81%

35Gooding County, IDID16,446+0.9%−96%

36Power County, IDID8,246+0.8%−88%

37Lemhi County, IDID8,474+0.5%−96%

38Clearwater County, IDID9,118-0.3%−106%

39Lincoln County, IDID5,603-1.6%−107%

40Custer County, IDID4,636-2.1%−142%

41Camas County, IDID1,316-3.6%−110%

42Lewis County, IDID3,704-7.5%−215%

43Butte County, IDID2,783-11.0%+1584%

44Clark County, IDID783-19.6%−157%

SHOWING 1–44 OF 44

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