List of the most populous counties in the United States in the context of "Chicago"

Los Angeles (LA) is the most populous city in the U.S. state of California, and the commercial, financial, and cultural center of Southern California. With an estimated 3.88 million residents within the city limits as of 2024, it is the second-most populous city in the United States, behind New York City. Los Angeles has an ethnically and culturally diverse population, and is the principal city of a metropolitan area of 12.9 million people (2024). Greater Los Angeles, a combined statistical area that includes the Los Angeles and Riverside–San Bernardino metropolitan areas, is a sprawling metropolis of over 18.5 million residents.

The majority of the city proper lies in the Los Angeles Basin adjacent to the Pacific Ocean in the west and extending partly through the Santa Monica Mountains and north into the San Fernando Valley, with the city bordering the San Gabriel Valley to its east. It covers about 469 square miles (1,210 km), and is the county seat and most populated city of Los Angeles County, which is the most populous county in the United States with an estimated 9.86 million residents as of 2022. It is the third-most visited city in the U.S. with over 2.7 million visitors as of 2023.

Hennepin County (/ˈhɛnəpɪn/ HEN-ə-pin) is a county in the U.S. state of Minnesota. As of the 2020 census, the population was 1,281,565, and was estimated to be 1,273,334 in 2024, making it the most populous county in Minnesota and the 34th-most populous county in the United States. Its county seat is Minneapolis, the most populous city in Minnesota and the 46th-most populous city in the United States. The county is named for the 17th-century explorer Louis Hennepin. It extends from Minneapolis to the suburbs and outlying cities in the western part of the county. Its natural areas are covered by extensive woods, hills, and lakes. It contains over 21.98% of the state's population. It is included in the Minneapolis–Saint Paul–Bloomington metropolitan statistical area.

Miami-Dade County (/maɪˈæmi ˈdeɪd/), known simply as Dade County prior to 1997, is a county located in the southeastern part of the U.S. state of Florida. The county had a population of 2,701,767 as of the 2020 census, making it the most populous county in Florida and the seventh-most-populous county in the United States. It is Florida's third largest county by land area with 1,946 square miles (5,040 km). The county seat is Miami, the core of the nation's sixth-largest and world's 65th-largest metropolitan area with a 2020 population of 6.138 million people, exceeding the population of 31 of the nation's 50 states as of 2022.

As of 2022, Miami-Dade County has a gross domestic product of $184.5 billion, making the county's GDP the largest for any county in the State of Florida and the 14th-largest for the nation's 3,033 counties. The county is home to the Port of Miami on Biscayne Bay, the world's largest passenger port with a world record 5.5 million passengers in 2018, and Miami International Airport, the third largest U.S. airport for international passengers and largest U.S. airport for international cargo. The county's land area of nearly 2,000 square miles (5,200 km) exceeds that of two U.S. states, Delaware and Rhode Island. The county is home to several universities and colleges, including Florida International University, one of the largest public universities in the country, and the University of Miami in Coral Gables, a private research university that is routinely ranked as one of the nation's top universities and is the county's second-largest employer with nearly 17,000 employees as of 2021.

Cook County is the most populous county in the U.S. state of Illinois and the second-most-populous county in the United States, after Los Angeles County, California. More than 40 percent of all residents of Illinois live within Cook County. As of 2020, the population was 5,275,541. The county seat is Chicago, the most populous city in Illinois and the third most populous city in the United States. The county is at the center of the Chicago metropolitan area.

Cook County was incorporated in 1831 and named for Daniel Pope Cook, an early Illinois statesman. It achieved its present boundaries in 1839. Within a century, the county recorded explosive population growth, going from a trading post village with a little over six hundred residents to four million, rivaling Paris by the Great Depression. During the first half of the 20th century, it had the absolute majority of Illinois's population.

San Bernardino County (/sæn ˌbɜːrnəˈdiːnoʊ/ SAN BUR-nə-DEE-noh), officially the County of San Bernardino, is a county located in the southern portion of the U.S. state of California, and is located within the Inland Empire area. As of the 2020 United States census, the population was 2,181,654, making it the fifth-most populous county in California and the 14th-most populous in the United States. The county seat is San Bernardino.

While included within the Greater Los Angeles area, San Bernardino County is included in the Riverside–San Bernardino–Ontario metropolitan statistical area.

33°44′N 115°59′W / 33.73°N 115.98°W / 33.73; -115.98

Riverside County is a county in the U.S. state of California. As of the 2020 census, its population was 2,418,185, making it the fourth-most populous county in California and the 10th-most populous in the United States. Located in Southern California, the county is named for the city of Riverside, which is its county seat.