Data / Rankings / Population density / Counties in Idaho

Counties in Idaho by population density

Ada County had the highest population density of 44 counties in 2020, at 182.8 inhabitants per km². Clark County had the lowest, at 0.2 inhabitants per km². The median was 3.6 inhabitants per km² and the figure for Idaho was 8.6 inhabitants per km². Source: the U.S. Census Bureau.

Highest182.8Ada County
Lowest0.2Clark County
Median3.644 counties
Idaho8.6History

All counties, 2020

CSVChart (SVG)

Ada CountyAda County: 182.8 inhabitants per km²182.8Canyon CountyCanyon County: 153.2 inhabitants per km²153.2Kootenai CountyKootenai County: 53.9 inhabitants per km²53.9Madison CountyMadison County: 43.6 inhabitants per km²43.6Bannock CountyBannock County: 30.3 inhabitants per km²30.3Bonneville CountyBonneville County: 25.8 inhabitants per km²25.8Payette CountyPayette County: 24.3 inhabitants per km²24.3Nez Perce CountyNez Perce County: 19.2 inhabitants per km²19.2Twin Falls CountyTwin Falls County: 18.2 inhabitants per km²18.2Jerome CountyJerome County: 15.7 inhabitants per km²15.7Latah CountyLatah County: 14.2 inhabitants per km²14.2Gem CountyGem County: 13.3 inhabitants per km²13.3Minidoka CountyMinidoka County: 11 inhabitants per km²11Jefferson CountyJefferson County: 11 inhabitants per km²11Bonner CountyBonner County: 10.6 inhabitants per km²10.6Teton CountyTeton County: 10.1 inhabitants per km²10.1Bingham CountyBingham County: 8.9 inhabitants per km²8.9Franklin CountyFranklin County: 8.3 inhabitants per km²8.3Gooding CountyGooding County: 8.3 inhabitants per km²8.3Benewah CountyBenewah County: 4.8 inhabitants per km²4.8Cassia CountyCassia County: 3.7 inhabitants per km²3.7Boundary CountyBoundary County: 3.7 inhabitants per km²3.7Elmore CountyElmore County: 3.6 inhabitants per km²3.6Blaine CountyBlaine County: 3.6 inhabitants per km²3.6Lewis CountyLewis County: 2.9 inhabitants per km²2.9Washington CountyWashington County: 2.8 inhabitants per km²2.8Fremont CountyFremont County: 2.8 inhabitants per km²2.8Bear Lake CountyBear Lake County: 2.5 inhabitants per km²2.5Power CountyPower County: 2.2 inhabitants per km²2.2Shoshone CountyShoshone County: 1.9 inhabitants per km²1.9Lincoln CountyLincoln County: 1.7 inhabitants per km²1.7Boise CountyBoise County: 1.6 inhabitants per km²1.6Caribou CountyCaribou County: 1.5 inhabitants per km²1.5Oneida CountyOneida County: 1.5 inhabitants per km²1.5Clearwater CountyClearwater County: 1.4 inhabitants per km²1.4Adams CountyAdams County: 1.3 inhabitants per km²1.3Valley CountyValley County: 1.2 inhabitants per km²1.2Idaho CountyIdaho County: 0.8 inhabitants per km²0.8Lemhi CountyLemhi County: 0.7 inhabitants per km²0.7Owyhee CountyOwyhee County: 0.6 inhabitants per km²0.6Butte CountyButte County: 0.4 inhabitants per km²0.4Camas CountyCamas County: 0.4 inhabitants per km²0.4Custer CountyCuster County: 0.3 inhabitants per km²0.3Clark CountyClark County: 0.2 inhabitants per km²0.2
inhabitants per km². Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-09.

Full ranking

RankCounties2020
inhabitants per km²
1Ada County182.8
2Canyon County153.2
3Kootenai County53.9
4Madison County43.6
5Bannock County30.3
6Bonneville County25.8
7Payette County24.3
8Nez Perce County19.2
9Twin Falls County18.2
10Jerome County15.7
11Latah County14.2
12Gem County13.3
13Minidoka County11
14Jefferson County11
15Bonner County10.6
16Teton County10.1
17Bingham County8.9
18Franklin County8.3
19Gooding County8.3
20Benewah County4.8
21Cassia County3.7
22Boundary County3.7
23Elmore County3.6
24Blaine County3.6
25Lewis County2.9
26Washington County2.8
27Fremont County2.8
28Bear Lake County2.5
29Power County2.2
30Shoshone County1.9
31Lincoln County1.7
32Boise County1.6
33Caribou County1.5
34Oneida County1.5
35Clearwater County1.4
36Adams County1.3
37Valley County1.2
38Idaho County0.8
39Lemhi County0.7
40Owyhee County0.6
41Butte County0.4
42Camas County0.4
43Custer County0.3
44Clark County0.2

Other periods

About this ranking

Resident population divided by land area in km². World Bank figures use mid-year population and land area excluding inland water.

United States: Census Bureau population estimates for 1 July divided by land area (water excluded) from the latest Census Gazetteer files. US tables often give people per square mile; multiply persons per km² by 2.59 to compare.

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. Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/. Retrieved 2026-10-09.

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Questions

Which county has the highest population density?

Ada County, with 182.8 inhabitants per km² in 2020, according to the U.S. Census Bureau.

Which county has the lowest population density?

Clark County, with 0.2 inhabitants per km² 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, Population Estimates Program resident population on 1 July divided by land area from the latest Census Gazetteer files, persons per km². Retrieved 2026-10-09.

Population density: other rankings

Counties in Idaho: more rankings