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List of Cities and Counties in Idaho

Discover Idaho population facts easily with our list of counties and cities. Find out how many people live in each area, from big cities to small towns, and see how Idaho’s population is spread out across the state.

Idaho Counties by Population

A county is an administrative subdivision of a US state or territory. As of 2022, Idaho is divided into 44 counties. 

The average population of Idaho counties is 43,203; Ada County is the most populous (511,931) and Clark County is the least (792). The average land area is 1882 sq mi. The largest county is Idaho County (8,485 sq mi) and the smallest is Payette County (408 sq mi).

read about the Population of Idaho

#CountyPopulation 2021Area
(sq. mi.)
(people/sq. mi)
1Ada County511,9311,055485.24
2Canyon County243,115590412.06
3Kootenai County179,7891,245144.41
4Bonneville County127,9301,86968.45
5Twin Falls County92,2431,92547.92
6Bannock County88,2631,11379.30
7Madison County53,881472114.15
8Bonner County49,4911,73828.48
9Bingham County48,8762,09523.33
10Nez Perce County42,45484950.00
11Latah County40,3131,07737.43
12Jefferson County32,2021,09529.41
13Elmore County28,8273,0789.37
14Payette County26,35040864.58
15Cassia County25,1642,5679.80
16Blaine County24,7662,6459.36
17Jerome County24,66260041.10
18Minidoka County21,95576028.89
19Gem County19,79256335.15
20Idaho County17,0408,4852.01
21Gooding County15,77273121.58
22Franklin County14,66666622.02
23Shoshone County13,6122,6345.17
24Fremont County13,5921,8677.28
25Boundary County12,5611,2699.90
26Owyhee County12,3367,6781.61
27Teton County12,26745027.26
28Valley County12,2413,7333.28
29Washington County10,8981,4567.48
30Benewah County9,93177612.80
31Clearwater County8,8952,4623.61
32Lemhi County8,1624,5641.79
33Boise County8,0941,9024.26
34Power County7,9501,4065.65
35Caribou County7,1111,7664.03
36Bear Lake County6,5459716.74
37Lincoln County5,2821,2064.38
38Adams County4,6251,3653.39
39Oneida County4,6111,2003.84
40Custer County4,4284,9260.90
41Lewis County3,7154797.76
42Butte County2,6542,2331.19
43Camas County1,1391,0771.06
44Clark County7921,7650.45

Source: US Census report 2021

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Top Cities in Idaho by population

Idaho is divided into 44 counties and contains 201 cities. The largest and most populated city in Idaho is State Capital, Boise (235,684).  It’s followed by Meridian (117,635)  and Nampa (100,200).

Let’s have a look at the top cities in Idaho by population

1Boise City235,684
4Idaho Falls64,818
7Coeur d’Alene54,628
8Twin Falls51,807

Source: US Census 2020

Most Populous Counties in Idaho

The most populous county in Idaho is Ada County with 511,931 residents. It was followed by Canyon County (243,115) and Kootenai County (179,789)

Let’s have a look at the Top 10 most populous counties

#CountyPopulation 2021
1Ada County511,931
2Canyon County243,115
3Kootenai County179,789
4Bonneville County127,930
5Twin Falls County92,243
6Bannock County88,263
7Madison County53,881
8Bonner County49,491
9Bingham County48,876
10Nez Perce County42,454
Least Populated Idaho County

The least populous county is Clark County with 792 residents, it’s followed by Camas County and Butte County.

Let’s have a look at 5 least populated counties in Idaho

#CountyPopulation 2021
1Clark County792
2Camas County1,139
3Butte County2,654
4Lewis County3,715
5Custer County4,428

source: US Census 2021

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Largest counties in Idaho by area

The Largest county by Land Area in Idaho is Idaho County with an area of 8,485 sq. miles. Owyhee County with an area of 7,678 sq. mi. comes next followed by Custer County (4,926 sq. mi.)

Let’s have a look at the Top 10 counties by Area

#CountyArea (sq. mi.)
1Idaho County8,485
2Owyhee County7,678
3Custer County4,926
4Lemhi County4,564
5Valley County3,733
6Elmore County3,078
7Blaine County2,645
8Shoshone County2,634
9Cassia County2,567
10Clearwater County2,462
Smallest County in Idaho by area

The smallest county by area in Idaho is Payette County with an area of 408 square miles.

#CountyArea (sq. mi.)
1Payette County408
2Teton County450
3Madison County472
4Lewis County479
5Gem County563

source: US Census report 2021

Most Densely populated Counties in Idaho

The most densely populated county in Idaho is Ada County, with 485 people per sq. mi. Next comes Canyon County with 412 people per sq. mi. followed by Kootenai County (144/ sq.mi)

Let’s have a look at the Top 10 densely populated counties

#CountyDensity (people/sq. mi)
1Ada County485.24
2Canyon County412.06
3Kootenai County144.41
4Madison County114.15
5Bannock County79.30
6Bonneville County68.45
7Payette County64.58
8Nez Perce County50.00
9Twin Falls County47.92
10Jerome County41.10
Least Densely Populated County in Idaho

Clark County with a population density of just 0.45 people per sq. miles is the least densely populated county in Idaho

#CountyDensity (people/sq. mi)
1Clark County0.45
2Custer County0.90
3Camas County1.06
4Butte County1.19
5Owyhee County1.61
List of Counties in Idaho 2024 | Top Cities in Idaho by population