RANKING · 2025 ESTIMATES · 44 SHOWN OF 44

Most densely populated, Idaho counties

Idaho counties ranked by residents per square mile (2025). This list covers the 44 counties in Idaho that qualify, ranked against each other statewide.

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

RANKPLACESTATEPOPPOPULATION DENSITYVS –

01Ada County, IDID546,141519–

02Canyon County, IDID275,123469–

03Kootenai County, IDID191,864155–

04Madison County, IDID55,172118–

05Bannock County, IDID91,59182–

06Bonneville County, IDID135,77173–

07Payette County, IDID27,82468–

08Twin Falls County, IDID97,53951–

09Nez Perce County, IDID42,90551–

10Jerome County, IDID26,36244–

11Gem County, IDID21,77339–

12Latah County, IDID41,84239–

13Jefferson County, IDID35,29732–

14Bonner County, IDID54,42031–

15Minidoka County, IDID22,91130–

16Teton County, IDID13,25430–

17Bingham County, IDID51,15324–

18Franklin County, IDID15,88924–

19Gooding County, IDID16,44623–

20Benewah County, IDID10,50814–

21Boundary County, IDID13,99711–

22Cassia County, IDID26,39710–

23Blaine County, IDID25,51710–

24Elmore County, IDID29,46510–

25Washington County, IDID11,5838–

26Lewis County, IDID3,7048–

27Fremont County, IDID14,2088–

28Bear Lake County, IDID6,7277–

29Power County, IDID8,2466–

30Shoshone County, IDID14,1305–

31Lincoln County, IDID5,6035–

32Boise County, IDID8,5454–

33Oneida County, IDID5,0854–

34Caribou County, IDID7,2524–

35Clearwater County, IDID9,1184–

36Adams County, IDID5,0134–

37Valley County, IDID12,8314–

38Idaho County, IDID17,8742–

39Lemhi County, IDID8,4742–

40Owyhee County, IDID12,6612–

41Butte County, IDID2,7831–

42Camas County, IDID1,3161–

43Custer County, IDID4,6361–

44Clark County, IDID7830–

SHOWING 1–44 OF 44

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UPDATED 2026-07-15 · DATA: US CENSUS BUREAU POPULATION ESTIMATES