The most populated county in every US state

Los Angeles
Los Angeles County is the most-populated in the country.
Andrew Zarivny/Shutterstock
  • Los Angeles County in California has more people than any other county in the US
  • The most recent US Census estimates, which were used in this story, are from July 2018.
  • Kings County, New York, home of the Brooklyn borough, is the largest county in New York state.
  • Visit for more stories.

You may know the largest city in every state but when it comes to counties, there can be a lot of surprises. We've rounded up the largest county, based on population numbers, in every state, so you don't have to do all of the hard work. 

It's important to note that these are subject to change as different areas boom and grow but is based on the most-recent Census estimates available from 2018. 

Jefferson County, Alabama

birmingham alabama
ESB Professional/Shutterstock

The US Census reports that there are 659,300 residents living in Jefferson County, Alabama. This makes it the largest county in the southern state. Jefferson County is also home to Birmingham, the capital of Alabama.

Anchorage Municipality, Alaska

Flickr / Doug Brown

As of July 2018, Anchorage Municipality had a population of 291,538 residents, per the US Census. In fact, 41% of the 49th state's residents live within Anchorage, according to Visit Anchorage.

Maricopa County, Arizona

phoenix, arizona

Over 4.4 million people call Maricopa County, Arizona home. Maricopa County includes Phoenix, the state's capital, and is located in the southern central region of the Grand Canyon. State.

Pulaski County, Arkansas

Little Rock, Arkansas
Little Rock
Sean Pavone / Shutterstock

Home to Little Rock — the capital of Arkansas and site of the William J. Clinton Presidential Library and Museum — Pulaski County is the most populous county in the state. According to Census reports, Pulaski County has an estimated 392,680 residents.

Los Angeles County, California

los angeles
Los Angeles
Sean Pavone/Shutterstock

Not only is Los Angeles County the largest county in California, but it's also the biggest county — population-wise — in the entire country. Census records show that more than 10 million people call the City of Angels (and its immediate surrounding area) home as of 2018.

County of Denver, Colorado

16th Street Mall Denver

The city and county of Denver contains a whopping 716,492 people, according to a 2018 estimate. 

Fairfield County, Connecticut

Bridgeport Connecticut
City of Bridgeport, CT - Government/Facebook

With an estimated population of 943,823, Fairfield County has more residents than any other county in Connecticut. Another fun fact about Fairfield County? Four major universities call the area home including Fairfield University, Sacred Heart University, University of Bridgeport, and Western Connecticut State University.

New Castle County, Delaware

Wilmington, Delaware

The entire state of Delaware only has a population of roughly 967,171 people, so don't expect to be blown away by the size of the biggest county. The bulk of those residents — 559,335 to be exact — live in New Castle County, making it the largest county in the tiny, mid-Atlantic state.


District of Columbia

washington dc
District of Columbia
Orhan Cam/Shutterstock

Given that the District of Columbia isn't a state, it doesn't have any counties. But, it's worth including in this roundup so you know just how many people live in the political pulse of the US. Per the US Census, the number of DC residents clocks in at roughly 702,455 as of July 2018.

Miami-Dade County, Florida

miami florida
Tono Balaguer/Shutterstock

More than 21 million people live in the Sunshine State and many of them live in Miami-Dade County. Home to the Miami Heat and beautiful Florida beaches, over 2.7 million Floridians reside in Miami, according to data from the US Census.

Fulton County, Georgia

the gulch atlanta
Looking east across The Gulch from Centennial Olympic Park Drive in Atlanta, Georgia.
Wikipedia Commons

Georgia may be best known for its delectable peaches, but did you know that Fulton County is the largest county in the historical state? Records show that over 1 million residents live within Fulton County limits, more than any other county in the state.

Honolulu County, Hawaii


Honolulu is one of the most well-known cities in Hawaii. But, did you know that Honolulu County is also the largest county in terms of population? Just over 980,000 people call themselves residents of Honolulu County.

Ada County, Idaho

Boise Idaho
Charles Knowles/Shutterstock

You can certainly find plenty of potatoes in Ada County, Idaho (including this one that's available to rent on Airbnb), but you can also find lots of people, too. Ada County, Idaho is the state's most populated county with roughly 469,966 residents as of July 2018.

Cook County, Illinois

chicago willis tower view

Chicago, one of the biggest cities in the US, falls smack dab in Cook County, Illinois. You don't have to connect many dots to realize that Cook County is the biggest county in Illinois with more than 5.1 million residents.

Marion County, Indiana

indianapolis indiana
Jonathan Weiss/Shutterstock

Out of the 92 counties in Indiana, Marion County is the winner when it comes to size. In fact, an estimated 954,670 people live in Marion County including residents of Indianapolis, according to the US Census

Polk County, Iowa

Des Moines, Iowa
Des Moines
Stephen Maturen / Stringer / Getty Images

The biggest county in Iowa, also known as the Hawkeye State, is Polk County. As of July 2018, approximately 487,204 people lived in Polk County. The midwest county is home to attractions like Adventureland Park and Blank Park Zoo.

Johnson County, Kansas

Kansas City
Kansas City
User:Charvex / Wikimedia Commons

Johnson County, Kansas has roughly 597,555 residents. As the biggest county in the 34th state, it's no wonder that the area has 16 libraries, six hospitals, 26 golf courses, and 44 fire stations.

Jefferson County, Kentucky

Louisville Kentucky

According to population numbers, the largest county in Kentucky is Jefferson County. The region has 770,517 residents as of July 2018 and encompasses the state's biggest city: Louisville.

East Baton Rouge Parish, Louisiana

baton rouge
Baton Rouge

In Louisiana, the land is divided by parishes instead of counties. So, what's the largest parish? It's the East Baton Rouge Parish, which, of course, includes the city of Baton Rouge. A total of more than 440,000 people live in the East Baton Rouge Parish.

Cumberland County, Maine

Portland, Maine

Cumberland County, which includes the coastal city of Portland, has 293,557 residents as of July 2018. Why does this matter? Well, that makes it the largest county within Maine.

Montgomery County, Maryland

Montgomery County, Maryland
Potomac, MD - May 30, 2018: An aerial drone view of an affluent residential neighborhood in Montgomery County

Located roughly 25 miles from the nation's capital is Montgomery County, Maryland. The total number of residents exceeds 1 million, making Montgomery County the largest county in the Old Line State.

Middlesex County, Massachusetts

cambridge best cities to live 2019
Songquan Deng/Shutterstock

Middlesex County, Massachusetts doesn't include all of Boston proper, but it does include several outlying neighborhoods including Waltham, Cambridge, Concord, and Somerville. The county boasts more than 1.6 million residents.

Wayne County, Michigan

detroit michigan 2017
Detroit, Michigan, in 2017.

It comes as no surprise that Wayne County is the largest county in Michigan. After all, the county includes Detroit — a major hub for the auto industry. As of July 2018, roughly 1,753,893 people live in Wayne County.

Hennepin County, Minnesota

minneapolis minnesota
The Spoonbridge and Cherry statue at the Minneapolis Sculpture Garden.

With more than 1.2 million residents, Hennepin County is the largest county in Minnesota. A total of 45 cities are inside Hennepin County lines.

Hinds County, Mississippi

Jackson Mississippi

What's the largest county in Mississippi? Hinds County. The area has an estimated 237,085 residents as of July 2018 and includes Jackson, the capital city of Mississippi.

St. Louis County, Missouri

st. louis
St. Louis

With almost 1 million residents, St. Louis County takes the No. 1 spot for the largest county in Missouri. The total number of residents in the eastern Missouri county is right around 996,945, according to US Census records.

Yellowstone County, Montana

billings montana
Billings, Montana.

Billings, Montana is smack dab in the middle of Yellowstone County, the largest county in all of Montana. The total headcount for the county is roughly 160,137. That's more than any other county in Big Sky Country.

Douglas County, Nebraska

castle rock
Castle Rock
Ian D. Keating/Flickr

An estimated 566,880 people live in Douglas County, Nebraska, according to US Census records. That means that Douglas County is the largest county Nebraska has to offer.

Clark County, Nevada

Las Vegas
Las Vegas is usually warm and there's a lot to do there.

The bright lights of Sin City are enough to designate Clark County as the largest county in Nevada. So, just how many people reside here? US Census estimates put the population count at over 2.2 million as of July 2018.

Hillsborough County, New Hampshire

manchester new hampshire
Mike Spenard/Wikimedia Commons

What county in New Hampshire has roughly 415,247 residents? It's Hillsborough County, of course. The county is also home to Manchester — the state's largest city.

Bergen County, New Jersey

Jersey City New Jersey
Bergen County
Walter Hickey / BI

The bright lights across the Hudson River can't outshine Bergen County, the largest county in New Jersey. Per Census estimates from July 2018, nearly 936,692 people live in Bergen County, New Jersey. That number makes it the largest county in the Garden State.

Bernalillo County, New Mexico

Albuquerque, New Mexico

Bernalillo County, New Mexico includes cities like Albuquerque, Los Ranchos, and Tijeras. With roughly 678,701 residents living in the county, Bernalillo is the largest county in New Mexico. 

Kings County, New York

Brooklyn, New York.

Move over Manhattan, Kings County (aka the Brooklyn Borough) is the latest county in New York State. More than 2.5 million people live in New York's largest county.

Mecklenburg County, North Carolina

charlotte nc

Located in the southwest part of North Carolina is Mecklenburg County. You may not recognize the county by name but you probably recognize Charlotte (the biggest city within county lines). It's the largest county in the state with 1,093,901 residents as of July 2018

Cass County, North Dakota

North Dakota State University
North Dakota State University
North Dakota State University

Cass County is the largest county in North Dakota. Of the 760,000-plus residents that live in Roughrider Country, roughly 181,000 of them live in Cass County.

Cuyahoga County, Ohio

cleveland ohio

With Cleveland as its pulse, Cuyahoga County is the largest county in Ohio. The county sits on Lake Erie and is home to more than 1.2 million people as of July 2018.

Oklahoma County, Oklahoma

Oklahoma City, Oklahoma
Oklahoma City

Oklahoma County, Oklahoma touts about 792,582 residents — including individuals who live in Oklahoma City. Its vast population makes it the largest county in Oklahoma.

Multnomah County, Oregon

Portland Oregon
Portland, Oregon

There are a total of 36 counties in Oregon, and of those counties, Multnomah is the largest. The county, which includes the metropolis of Portland, has roughly 811,880 residents.

Philadelphia County, Pennsylvania

Philadelphia, Pennsylvania.
Roman Babakin/Shutterstock

Philadelphia has great cheesesteaks, the Liberty Bell, a few major sports teams, but did you know that Philadelphia County is the largest county in the state? With more than 1.5 million estimated residents, it's worth noting that Philadelphia County takes first place in size.

Providence County, Rhode Island

providence rhode island
Providence, Rhode Island

Rhode Island is a tiny slice of New England. In fact, the state is only made up of five counties. So, what's the largest one? According to US Census data, Providence County is the winner with roughly 636,084 residents.

Greenville County, South Carolina

Greenville, South Carolina
Greenville, South Carolina
Cvandyke / Shutterstock

Located in the northern part of South Carolina, Greenville County is home to about 514,213 people. The city of Greenville, located within the county, boasts a mild climate with an average annual temperature of 60 degrees Fahrenheit and the largest public school system in the state. 

Minnehaha County, South Dakota

Sioux Falls
Sioux Falls
Jon Platek/Wikimedia Commons

Founded in 1862, Minnehaha County is the largest county in South Dakota. According to data from the US Census Bureau, roughly 192,876 people reside within the county. For that reason, it's the biggest county in the entire state.

Shelby County, Tennessee

memphis tennessee
Memphis, Tennessee.
Sean Pavone/Shutterstock

Shelby County, Tennessee has a couple of claims to fame. Not only does it encompass Memphis, the home of the Blues, but it is also the largest county in the Volunteer State. More than 935,000 people live in Shelby County, according to the US Census.

Harris County, Texas

houston night
An ideal destination for museum lovers.
eflon/Flickr/Some Rights Reserved

Of the 254 counties in Texas, Harris County takes the cake for the largest. The county includes the city of Houston, which helps contribute to its robust population numbers. More than 4.6 million people live in Harris County as of July 2018, according to the most recent Census numbers.

Salt Lake County, Utah

Salt Lake
Salt Lake City, Utah.
Skyguy414 / Wikimedia Commons

Salt Lake County is known for more than its snow-covered mountain tops and summertime nature hikes — it's also the largest county in Utah. More than 1.1 million residents called Salt Lake County home as of July 2018.

Chittenden County, Vermont

Church Street Marketplace burlington vermont
Church Street Marketplace in Burlington.
Sean Pavone/Shutterstock

Chittenden County has the prestigious honor of being home to Ben & Jerry's, but it's also noteworthy for another reason. It's the largest county in Vermont, touting more than roughly 164,000 residents.

Fairfax County, Virginia

Fairfax County, Virginia
Lake Anne Reston Virginia Luxury Lakefront Townhomes Fairfax County

If you work in Washington DC, there's a high chance you probably live in Virginia's largest county. As of July 2018, Census records show that Fairfax County had more than 1.1 million residents.

King County, Washington

Mt Rainier, Seattle, Space Needle
The Seattle skyline featuring the Space Needle and Mt. Rainier.

Out in the pacific northwest, King County is the top contender for the largest county in Washington State. The area, which includes Seattle, is home to more than 2.2 million people.

Kanawha County, West Virginia

Charleston, West Virginia
Charleston, West Virginia.

Home to Charleston, West Virginia's state capital, is Kanawha County. Recent Census numbers show that just about 180,454 people call the county home, making it the biggest county in West Virginia.

Milwaukee County, Wisconsin

Milwaukee Wisconsin
Milwaukee, Wisconsin.

There's no if, ands, or buts about it — Milwaukee County is the largest county in Wisconsin. More than 948,000 people called Milwaukee County home as of July 2018.

Laramie County, Wyoming

cheyenne wyoming state capitol building
Cheyenne's state capitol building.
Henryk Sadura/Shutterstock

Last, but certainly not least, is Laramie County, Wyoming. It's the largest county in the Cowboy State. As of July 2018, the resident count was sitting right below the six-figure mark at an estimated 98,976 residents.

SEE ALSO: 17 of the best state fairs in the US, ranked

FOLLOW US: INSIDER is on Facebook

Close icon Two crossed lines that form an 'X'. It indicates a way to close an interaction, or dismiss a notification.