Data / Rankings / Population / Counties in Idaho

Counties in Idaho by population

Ada County had the highest population of 44 counties in 2020, at 498,263. Clark County had the lowest, at 791. The median was 13,852 and the figure for Idaho was 1.85 million. Source: the U.S. Census Bureau.

Highest498,263Ada County
Lowest791Clark County
Median13,85244 counties
Idaho1,849,328History

All counties, 2020

CSVChart (SVG)

Ada CountyAda County: 498,263 persons498,263Canyon CountyCanyon County: 233,001 persons233,001Kootenai CountyKootenai County: 172,797 persons172,797Bonneville CountyBonneville County: 124,730 persons124,730Twin Falls CountyTwin Falls County: 90,365 persons90,365Bannock CountyBannock County: 87,294 persons87,294Madison CountyMadison County: 52,950 persons52,950Bingham CountyBingham County: 48,097 persons48,097Bonner CountyBonner County: 47,411 persons47,411Nez Perce CountyNez Perce County: 42,148 persons42,148Latah CountyLatah County: 39,633 persons39,633Jefferson CountyJefferson County: 31,080 persons31,080Elmore CountyElmore County: 28,670 persons28,670Payette CountyPayette County: 25,577 persons25,577Cassia CountyCassia County: 24,753 persons24,753Blaine CountyBlaine County: 24,341 persons24,341Jerome CountyJerome County: 24,269 persons24,269Minidoka CountyMinidoka County: 21,669 persons21,669Gem CountyGem County: 19,275 persons19,275Idaho CountyIdaho County: 16,592 persons16,592Gooding CountyGooding County: 15,647 persons15,647Franklin CountyFranklin County: 14,284 persons14,284Fremont CountyFremont County: 13,420 persons13,420Shoshone CountyShoshone County: 13,198 persons13,198Boundary CountyBoundary County: 12,141 persons12,141Owyhee CountyOwyhee County: 11,993 persons11,993Valley CountyValley County: 11,841 persons11,841Teton CountyTeton County: 11,740 persons11,740Washington CountyWashington County: 10,556 persons10,556Benewah CountyBenewah County: 9,580 persons9,580Clearwater CountyClearwater County: 8,758 persons8,758Lemhi CountyLemhi County: 7,955 persons7,955Power CountyPower County: 7,880 persons7,880Boise CountyBoise County: 7,662 persons7,662Caribou CountyCaribou County: 7,013 persons7,013Bear Lake CountyBear Lake County: 6,365 persons6,365Lincoln CountyLincoln County: 5,137 persons5,137Oneida CountyOneida County: 4,564 persons4,564Adams CountyAdams County: 4,423 persons4,423Custer CountyCuster County: 4,269 persons4,269Lewis CountyLewis County: 3,534 persons3,534Butte CountyButte County: 2,581 persons2,581Camas CountyCamas County: 1,081 persons1,081Clark CountyClark County: 791 persons791
persons. Source: U.S. Census Bureau. Retrieved 2026-10-08.

Full ranking

RankCounties2020
persons
1Ada County498,263
2Canyon County233,001
3Kootenai County172,797
4Bonneville County124,730
5Twin Falls County90,365
6Bannock County87,294
7Madison County52,950
8Bingham County48,097
9Bonner County47,411
10Nez Perce County42,148
11Latah County39,633
12Jefferson County31,080
13Elmore County28,670
14Payette County25,577
15Cassia County24,753
16Blaine County24,341
17Jerome County24,269
18Minidoka County21,669
19Gem County19,275
20Idaho County16,592
21Gooding County15,647
22Franklin County14,284
23Fremont County13,420
24Shoshone County13,198
25Boundary County12,141
26Owyhee County11,993
27Valley County11,841
28Teton County11,740
29Washington County10,556
30Benewah County9,580
31Clearwater County8,758
32Lemhi County7,955
33Power County7,880
34Boise County7,662
35Caribou County7,013
36Bear Lake County6,365
37Lincoln County5,137
38Oneida County4,564
39Adams County4,423
40Custer County4,269
41Lewis County3,534
42Butte County2,581
43Camas County1,081
44Clark County791

Other periods

About this ranking

Resident population. Spain and the EU: 1 January, with Spanish figures from the official municipal register (Padrón). United States: Census Bureau population estimates for 1 July. Other countries and the World: World Bank mid-year estimates, which count all residents regardless of legal status or citizenship.

For Denmark, Statistics Denmark counts the registered resident population on 1 January. Greenland and the Faroe Islands are excluded. The annual series selects the first-quarter reference date from FOLK1A. The World Bank series exists for every country, so use it (through compare) to rank countries on one basis.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-08.

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Questions

Which county has the highest population?

Ada County, with 498,263 in 2020, according to the U.S. Census Bureau.

Which county has the lowest population?

Clark County, with 791 in 2020.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Annual estimates of the resident population for the United States, states and counties, 1 July (Population Estimates Program). Retrieved 2026-10-08.

Population: other rankings

Counties in Idaho: more rankings