Data / Rankings / Population density / Counties in Idaho

Counties in Idaho by population density

Ada County had the highest population density of 44 counties in 2021, at 188.3 inhabitants per km². Clark County had the lowest, at 0.2 inhabitants per km². The median was 3.7 inhabitants per km² and the figure for Idaho was 8.9 inhabitants per km². Source: the U.S. Census Bureau.

Highest188.3Ada County
Lowest0.2Clark County
Median3.744 counties
Idaho8.9History

All counties, 2021

CSVChart (SVG)

Ada CountyAda County: 188.3 inhabitants per km²188.3Canyon CountyCanyon County: 160.3 inhabitants per km²160.3Kootenai CountyKootenai County: 56.2 inhabitants per km²56.2Madison CountyMadison County: 44.5 inhabitants per km²44.5Bannock CountyBannock County: 30.8 inhabitants per km²30.8Bonneville CountyBonneville County: 26.5 inhabitants per km²26.5Payette CountyPayette County: 25 inhabitants per km²25Nez Perce CountyNez Perce County: 19.4 inhabitants per km²19.4Twin Falls CountyTwin Falls County: 18.6 inhabitants per km²18.6Jerome CountyJerome County: 16 inhabitants per km²16Latah CountyLatah County: 14.4 inhabitants per km²14.4Gem CountyGem County: 13.7 inhabitants per km²13.7Jefferson CountyJefferson County: 11.4 inhabitants per km²11.4Minidoka CountyMinidoka County: 11.2 inhabitants per km²11.2Bonner CountyBonner County: 11.1 inhabitants per km²11.1Teton CountyTeton County: 10.6 inhabitants per km²10.6Bingham CountyBingham County: 9 inhabitants per km²9Franklin CountyFranklin County: 8.5 inhabitants per km²8.5Gooding CountyGooding County: 8.4 inhabitants per km²8.4Benewah CountyBenewah County: 4.9 inhabitants per km²4.9Boundary CountyBoundary County: 3.8 inhabitants per km²3.8Cassia CountyCassia County: 3.8 inhabitants per km²3.8Elmore CountyElmore County: 3.6 inhabitants per km²3.6Blaine CountyBlaine County: 3.6 inhabitants per km²3.6Lewis CountyLewis County: 3 inhabitants per km²3Washington CountyWashington County: 2.9 inhabitants per km²2.9Fremont CountyFremont County: 2.8 inhabitants per km²2.8Bear Lake CountyBear Lake County: 2.6 inhabitants per km²2.6Power CountyPower County: 2.2 inhabitants per km²2.2Shoshone CountyShoshone County: 2 inhabitants per km²2Lincoln CountyLincoln County: 1.7 inhabitants per km²1.7Boise CountyBoise County: 1.7 inhabitants per km²1.7Caribou CountyCaribou County: 1.6 inhabitants per km²1.6Oneida 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: 1.3 inhabitants per km²1.3Idaho 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: 0.5 inhabitants per km²0.5Camas 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

RankCounties2021
inhabitants per km²		Change on 2020
1Ada County188.3+3%
2Canyon County160.3+4.6%
3Kootenai County56.2+4.2%
4Madison County44.5+2.2%
5Bannock County30.8+1.5%
6Bonneville County26.5+2.7%
7Payette County25+3.1%
8Nez Perce County19.4+0.9%
9Twin Falls County18.6+2.2%
10Jerome County16+1.9%
11Latah County14.4+1.9%
12Gem County13.7+2.7%
13Jefferson County11.4+3.6%
14Minidoka County11.2+1.3%
15Bonner County11.1+4.7%
16Teton County10.6+4.6%
17Bingham County9+1.7%
18Franklin County8.5+2.7%
19Gooding County8.4+1%
20Benewah County4.9+3.3%
21Boundary County3.8+4%
22Cassia County3.8+2%
23Elmore County3.6+1.1%
24Blaine County3.6+1.8%
25Lewis County3+4.8%
26Washington County2.9+3.3%
27Fremont County2.8+1.2%
28Bear Lake County2.6+3.2%
29Power County2.2+1.3%
30Shoshone County2+3.1%
31Lincoln County1.7+3%
32Boise County1.7+6.3%
33Caribou County1.6+1.4%
34Oneida County1.5+0.9%
35Clearwater County1.4+2%
36Adams County1.3+4.5%
37Valley County1.3+3.5%
38Idaho County0.8+2.8%
39Lemhi County0.7+2.5%
40Owyhee County0.6+3%
41Butte County0.5+3.1%
42Camas County0.4+4.9%
43Custer County0.3+4.2%
44Clark County0.2+0.6%

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 188.3 inhabitants per km² in 2021, according to the U.S. Census Bureau.

Which county has the lowest population density?

Clark County, with 0.2 inhabitants per km² in 2021.

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