In this article, we take a look at the 5 Most Populated Counties in the US. If you want to see our detailed discussion of the topic, go to 20 Most Populated Counties in the US.
5. San Diego County, California
Population Estimates (2023): 3,269,973
Ranked 5th, San Diego County has a diverse racial population, with 74.4% White, 13.1% Asian, and 35.0% Hispanic or Latino populations. It is the 9th largest county by land area in California and is bordered by Imperial County, Orange County, and Riverside County. The county has an employment rate of 59.9% and a median household income of over $97,000. Moreover, the educational demographics are strong in the county too, with 43% of the people having attained a bachelor’s degree or higher.
4. Maricopa County, Arizona
Population Estimates (2023): 4,585,871
With a population of 4.5 million, Maricopa County is the fourth largest county by population in the US, and the 5th largest in Arizona by area. About 8.2% of individuals under 65 in Maricopa County live with disabilities, and 10.5% of the population lacks health care coverage. At the same time, there are about 104,022 employer establishments in the county and it has a median household income of $83,747.
3. Harris County, Texas
Population Estimates (2023): 4,835,125
Ranked 3rd among the counties with the highest population, Harris County is the 14th largest county in Texas by total area, spanning across 1,707.0 sq. miles. The county houses approximately 4.83 million individuals, out of which 68.5% are White, 7.5% are Asian, and 44.6% are Hispanic or Latino. Moreover, Harris County has an employment rate of 63.8%, 108,434 employer establishments, and a median household income of $68,706.
2. Cook County, Illinois
Population Estimates (2023): 5,087,072
Second on the list of most populated counties in the US, Cook County experienced a 3.6% population decline from 2020 to 2023, bringing the population count down to 5,087,072 from 5,275,555. By total area, Cook County spans across 944.9 sq. miles, and is the 6th largest county in the state of Illinois.
Moreover, a whopping 42.4% of the residents in Cook County have attained a bachelor’s degree or higher, which demonstrates the educational enthusiasm of the Cook County residents. If we look at the economy in the county, we see that it houses 134,715 employer establishments and 62.5% of the working residents are employed. Also, according to the Census data, the median household income in Cook County is only $76 lower than the median household income in Illinois, standing at $76,632 as of 2024.
1. Los Angeles County, California
Population Estimates (2023): 9,663,345
Los Angeles County ranked as the most populated county in the US with a staggering 9.6 million residents, is a melting pot of diversity. According to the Census Bureau’s data, approximately 70.0% of residents are White, while 15.8% are Asian, and 49.0% are Hispanic or Latino. Amidst this rich tapestry of cultures, 64.7% of the population actively participates in the labor force, contributing to the county’s thriving economy, with a median household income of over $83,000. It is the 11th largest county in the state by overall area.
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