In this article, we list and discuss the 20 Largest Counties in the US by Area. You can also check out 30 Largest Cities in the US by Area.
The fourth-largest country in the world, the United States, has 3,143 counties spread across more than 9.3 million square kilometers of land. In the US, a county is an administrative or political unit consisting of a geographic area and a collection of some cities and towns. It is a term used in all states of the US, except for Louisiana and Alaska, where terms like boroughs, parishes, and census areas (county-equivalent subdivisions) replace the term “county.”
Counties vary greatly in size, population, and population density. For example, all the counties we have listed in this article have a land area of over 10,500 square miles, which makes them larger than some US states like Massachusetts, Vermont, and New Hampshire. On the other hand, with a land area of just 12 square miles, Kalawao County is the smallest county in the US by area and has a population of 82 people. Furthermore, the largest county or county equivalent by area in the US has a population of just 5,129 people, making it one of the least densely populated counties. To find out which one it is, keep reading the article.
The discrepancy in population distribution in counties is the result of several factors, including economic opportunities and ease of living. For instance, Alaska, the largest state in the US, has a population density of only 1.3 people per square mile. Due to the challenging geographic location of the state, all Boroughs and Parishes in Alaska have extremely high living costs. Additionally, the challenging geographic conditions of Alaska have resulted in very little infrastructure development, which has further deviated the residents to shift elsewhere.
However, every cloud has a silver lining. Looking at large US counties from a business perspective, there are ample development projects and land uses in counties, which can be realized by construction companies in the US. Some key players in the construction industry include AECOM (NYSE:ACM), Fluor Corp (NYSE:FLR), and Jacobs Solutions Inc (NYSE:J).
In October 2022, AECOM (NYSE:ACM)’s joint venture with W.M. Lyles was awarded a contract by the Joint Powers Authority to support the East County Advanced Water Purification Program in San Diego County, California. AECOM (NYSE:ACM) is an American multinational infrastructure consulting firm and was awarded this contract for its vast experience in the industry. In this program, the AECOM (NYSE:ACM) team extends its services to create a new local, safe, sustainable, and drought-proof drinking water supply. The program, scheduled to end in 2026, will approximately meet 30% of the current drinking water supply for residents and businesses in East San Diego County.
Meanwhile, Fluor Corporation (NYSE: FLR) announced in July 2023 that the US Department of Energy (DOE) selected Southern Ohio Cleanup Company, LLC, a joint venture led by Amentum with Fluor Corp (NYSE: FLR) and Cavendish Nuclear USA, to execute the Portsmouth Gaseous Diffusion Plant Decontamination and Decommissioning Contract in Pike County, Ohio. With an estimated value of $5.87 billion, the project has over a 10-year ordering period.
On the other hand, Jacobs Solutions Inc (NYSE:J), a US-based international technical professional services firm, is collaborating with the City and County of Denver (CCD) to transform a 110-acre historic site, the National Western Center (NWC), into a 250-acre sustainable destination for agriculture, education, and entertainment. This collaboration with Jacobs Solutions Inc (NYSE:J) offers an opportunity to connect the rural and urban economies. Initially, the site hosted bustling livestock markets but now will host concerts and festivals as well as sporting events, trade shows, and business events.
Also see 15 Fastest Growing Cities in Tennessee and 10 Fastest Growing Cities in Kentucky.
Our Methodology
For our list of the 20 Largest Counties in the US by Area, we compared the state map with a map of US counties to first roughly identify the states with the largest counties by area. We then used data from the US Census Bureau to list down the area of all counties and county-equivalents within these states to identify the largest counties in the US by Area. The list is in ascending order of the total land area of each county in square miles. All other data mentioned in the list has been sourced from the US Census Bureau.
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20 Largest Counties in the US by Area
20. Lincoln County, Nevada
Total Land Area (in square miles): 10,633.40
Situated in Nevada, Lincoln County spans more than 10,600 square miles and is home to around 4,452 people. The population density in the county is 0.4 people per square mile, with around 88.2% of the population having attained higher education. On the downside, 10.5% of the people in the county do not have healthcare coverage.
19. Apache County, Arizona
Total Land Area (in square miles): 11,198.30
Ranked 19th, Apache County is located in Arizona and is one of the Largest Counties in the US by Area. With a median rent of over $680 and a median household income of $37,663, Apache County does not do quite well on the economic forefront and has a high poverty rate of 28.1%.
18. Denali Borough, Alaska
Total Land Area (in square miles): 12,641.00
Denali Borough is Alaska’s 13th-largest county by total area. Of the 1,584 people living here, 25.1% have attained a bachelor’s degree or higher, and around 60% are in K-12 schooling. The median household income in the county stands at $87,292, while the poverty rate stands at 7.3%, and the median gross rent stands at $863.
17. Mohave County, Arizona
Total Land Area (in square miles): 13,332.10
Mohave County is the 2nd largest county in Arizona by total area, with a population of 223,682, a population growth rate of 4.9%, and a population density of 16 people per square mile. Although the county has diverse industries, including retail trade, healthcare, professional services, and construction, it does not offer many job opportunities to its residents. Overall, the county has an employment rate of 41.5%.
16. Kenai Peninsula Borough, Alaska
Total Land Area (in square miles): 16,017.40
Ranked 16th, the Kenai Peninsula Borough is the 12th largest county in Alaska by total area. The county has a diverse population of 61,223 individuals, composed of 82.2% White, 1.9% Asian, and 4.6% Hispanic or Latino people. Moreover, 57.1% of the county residents are in the labor force.
15. Kusilvak Census Area, Alaska
Total Land Area (in square miles): 17,077.10
Kusilvak Census Area, the 11th largest county in Alaska by total area, is home to a population of around 8,000 individuals. With a 47.0% employment rate, key industries like agriculture, healthcare, and public administration lead the charge. However, the county has a median household income of $42,663, which is well below the state average. Resultantly, the county has a poverty rate of 34.3%.
14. Elko County, Nevada
Total Land Area (in square miles): 17,173.40
Elko County, the second-largest county by total area in Nevada, is home to around 38,000 individuals. Out of these, 17% have attained higher education, and 63.9% are employed with a median household income of $87,755.
13. Nye County, Nevada
Total Land Area (in square miles): 18,181.90
Nye County, the largest county in Nevada by total area, is the 13th largest county by area in the US. With a population of nearly 56,000 people, Nye County has a 75.1% owner-occupied housing rate and a 37.9% employment rate with a median household income of approximately $54,000.
12. Dillingham Census Area, Alaska
Total Land Area (in square miles): 18,334.00
12th on the list and 10th largest county in Alaska by total area, with a population change of -5.1%, the Dillingham Census Area has about 4,600 people. The ethnic makeup of this county showcases 15.4% White, 1.1% Asian, and 3.6% Hispanic or Latino residents. Moreover, 20.5% of these people have attained higher education.
11. Coconino County, Arizona
Total Land Area (in square miles): 18,616.40
Ranked 11th, Coconino County is the largest county in Arizona by total area and went through a small population decline of -0.4% from 2020 to 2023. 9.5% under 65 are facing disabilities and 14.3% lack health insurance, signaling areas for improvement. At the same time, however, the county has an employment rate of 58.8%, and a median gross rent of $1,284.
10. San Bernardino County, California
Total Land Area (in square miles): 20,068.20
First on the list of the 10 largest counties by area in the US, San Bernardino County is the largest county in California, by land area. With a population of over 2 million, and a population density of 108.7 people per square mile, San Bernardino is also one of the largest counties in the US by population. In terms of diversity, the county is home to 75.3% white residents, 8.9% Asians, and 56.2% Hispanic or Latino individuals.
9. Nome Census Area, Alaska
Total Land Area (in square miles): 22,969.50
Ranked 9th on the list, Nome Census Area is also the 9th largest county in Alaska by total area. With a solid 62.6% homeownership rate, out of the 4,095 total units, 3,030 houses in this county are occupied. Moreover, the Nome Census Area has a population of 9,763 people and a population density of 0.4 people per square mile. Of these, 18.3% have attained higher education, while 54.3% are employed.
8. Lake and Peninsula Borough, Alaska
Total Land Area (in square miles): 23,831.80
Lake and Peninsula Borough is the 8th largest county in Alaska by total area as well as the 8th largest county by area in the country. The county has a population of 1,331 people, of which 15.5% have attained higher education, and 63.8% are employed. The population density in this county of Alaska is 0.1 people per square mile.
7. Copper River Census Area, Alaska
Total Land Area (in square miles): 24,692.10
7th on the list, the Copper River Census Area is home to over 2,600 people, which brings the county’s population density to about 0.1 people per square mile. The median household income in the county is $70,606, while the poverty rate stands at 11.2%. Moreover, the county has an employment rate of 56.7% and about 2,769 housing units.
6. Matanuska-Susitna Borough, Alaska
Total Land Area (in square miles): 24,706.97
With a population of 115,239 people, a population density of 4.3 people per square mile, and a land area of nearly 24,707 square miles, the Matanuska-Susitna Borough of Alaska is the 6th largest county by area in the US. In this county, 56.3% of the residents are employed, and the employment sectors vary widely. Construction and retail trade sectors lead the way, while education, healthcare, transportation, and public administration also contribute to shaping the borough’s economic landscape.
5. Southeast Fairbanks Census Area, Alaska
Total Land Area (in square miles): 24,831.10
Fifth on the list, the Southeast Fairbanks Census Area of Alaska is home to around 7,077 people. The housing landscape in the county is quite healthy, with 75.0% of the total housing units being owner-occupied, boasting a median value of $222,200. Additionally, the median household income in the county stands at $75,378.
