Even as the U.S. population ages and the birth rate declines, there are counties in each state where the median age is lower than the national median of 38.
To determine the county with the youngest population in every state, 24/7 Tempo reviewed five-year data on median age in each county or county equivalent from the U.S. Census Bureau’s 2020 American Community Survey. Counties were ranked based on the median age of all residents. In the case of a tie, the county with the largest share of population under age 18 ranked as the youngest.
Supplemental data on the share of the population under 18 years old and total population are five-year estimates and also came from the 2020 ACS. Data on population and place boundaries used to determine the largest city, town, or census designated place in every county came from the Census Bureau.
Among the reasons why certain areas have younger demographics than others are the presence of large universities, military bases, and dynamic economic sectors.
The vast majority of the 19.6 million college and university students in the United States are under 25 years old, and the presence of a postsecondary institution can lower the median age of any county. That is the case in places such as Tolland County in Connecticut, home to the University of Connecticut; Centre County in Pennsylvania, where Penn State University is located; and Leon County, Florida, home to Florida State University and Florida A&M. (These are the 30 best college towns in America.)
Some counties on this list are home to military bases and installations. These include Christian County in Kentucky, home of the massive Fort Campbell; Onslow County, North Carolina, site of the storied Camp Lejeune Marine Corps base; and Riley County, Kansas, where Fort Riley is located. Age ceilings for enlistment in the U.S. armed services contribute to lower median age in these areas. (These are America’s 25 military cities.)
Another reason certain areas have younger demographics is the presence of robust economic sectors. The biggest city in New Jersey’s Hudson County is Jersey City, across the Hudson River from New York City. In recent years, Jersey City has become a financial industry powerhouse. This has led to an upsurge in housing redevelopment, a vibrant nightlife, and a surge in younger residents.
Many of the counties that are the youngest in their respective states are also the most populous, among them Utah County in Utah; Chittenden in Vermont; and Providence in Rhode Island. Twenty-two of the counties on the list have a median age under 30 years old.
Alabama: Pike County
> Median Age: 30.8 years (state: 39.2 years)
> Population under 18: 18.9% (state: 22.3%)
> Population 65 and over: 15.4% (state: 16.9%)
> Total population: 33,274
> Largest city or town in county : Troy
Alaska: Kusilvak Census Area
> Median Age: 24.1 years (state: 34.6 years)
> Population under 18: 40.5% (state: 24.9%)
> Population 65 and over: 5.8% (state: 11.9%)
> Total population: 8,298
> Largest city or town in county : Hooper Bay
Arizona: Coconino County
> Median Age: 31.0 years (state: 37.9 years)
> Population under 18: 20.4% (state: 22.9%)
> Population 65 and over: 12.6% (state: 17.6%)
> Total population: 142,254
> Largest city or town in county : Flagstaff
Arkansas: Washington County
> Median Age: 32.2 years (state: 38.3 years)
> Population under 18: 24.3% (state: 23.3%)
> Population 65 and over: 11.7% (state: 16.9%)
> Total population: 236,198
> Largest city or town in county : Fayetteville
California: Yolo County
> Median Age: 31.1 years (state: 36.7 years)
> Population under 18: 21.0% (state: 22.8%)
> Population 65 and over: 12.5% (state: 14.3%)
> Total population: 218,774
> Largest city or town in county : Davis
Colorado: Alamosa County
> Median Age: 32.3 years (state: 36.9 years)
> Population under 18: 24.2% (state: 22.1%)
> Population 65 and over: 13.9% (state: 14.2%)
> Total population: 16,153
> Largest city or town in county : Alamosa
Connecticut: Tolland County
> Median Age: 37.6 years (state: 41.1 years)
> Population under 18: 17.3% (state: 20.6%)
> Population 65 and over: 15.8% (state: 17.2%)
> Total population: 150,947
> Largest city or town in county : Storrs
Delaware: Kent County
> Median Age: 38.1 years (state: 41.0 years)
> Population under 18: 23.0% (state: 21.1%)
> Population 65 and over: 17.1% (state: 18.8%)
> Total population: 179,124
> Largest city or town in county : Dover
Florida: Leon County
> Median Age: 31.3 years (state: 42.2 years)
> Population under 18: 18.6% (state: 19.9%)
> Population 65 and over: 13.4% (state: 20.5%)
> Total population: 291,863
> Largest city or town in county : Tallahassee
Georgia: Chattahoochee County
> Median Age: 24.0 years (state: 36.9 years)
> Population under 18: 20.9% (state: 23.8%)
> Population 65 and over: 3.0% (state: 13.9%)
> Total population: 10,470
> Largest city or town in county : Cusseta-Chattahoochee County
Hawaii: Honolulu County
> Median Age: 38.2 years (state: 39.4 years)
> Population under 18: 21.1% (state: 21.3%)
> Population 65 and over: 17.8% (state: 18.4%)
> Total population: 979,682
> Largest city or town in county : Urban Honolulu
Idaho: Madison County
> Median Age: 23.5 years (state: 36.6 years)
> Population under 18: 26.9% (state: 25.3%)
> Population 65 and over: 6.7% (state: 15.8%)
> Total population: 39,725
> Largest city or town in county : Rexburg
Illinois: Champaign County
> Median Age: 30.4 years (state: 38.3 years)
> Population under 18: 18.9% (state: 22.5%)
> Population 65 and over: 12.8% (state: 15.7%)
> Total population: 210,006
> Largest city or town in county : Champaign
Indiana: Tippecanoe County
> Median Age: 28.4 years (state: 37.8 years)
> Population under 18: 20.5% (state: 23.5%)
> Population 65 and over: 11.4% (state: 15.7%)
> Total population: 193,302
> Largest city or town in county : Lafayette
Iowa: Story County
> Median Age: 26.8 years (state: 38.3 years)
> Population under 18: 16.5% (state: 23.1%)
> Population 65 and over: 12.2% (state: 17.1%)
> Total population: 97,355
> Largest city or town in county : Ames
Kansas: Riley County
> Median Age: 25.4 years (state: 36.9 years)
> Population under 18: 16.5% (state: 24.2%)
> Population 65 and over: 9.2% (state: 15.8%)
> Total population: 74,059
> Largest city or town in county : Manhattan
Kentucky: Christian County
> Median Age: 28.3 years (state: 39.0 years)
> Population under 18: 27.1% (state: 22.6%)
> Population 65 and over: 12.3% (state: 16.4%)
> Total population: 71,470
> Largest city or town in county : Hopkinsville
Louisiana: Lincoln Parish
> Median Age: 28.1 years (state: 37.2 years)
> Population under 18: 20.0% (state: 23.5%)
> Population 65 and over: 13.6% (state: 15.4%)
> Total population: 47,118
> Largest city or town in county : Ruston
Maine: Androscoggin County
> Median Age: 40.7 years (state: 44.8 years)
> Population under 18: 21.7% (state: 18.7%)
> Population 65 and over: 17.6% (state: 20.6%)
> Total population: 107,958
> Largest city or town in county : Lewiston
Maryland: Baltimore County
> Median Age: 35.5 years (state: 38.8 years)
> Population under 18: 20.5% (state: 22.2%)
> Population 65 and over: 14.0% (state: 15.4%)
> Total population: 602,274
> Largest city or town in county : Baltimore
Massachusetts: Suffolk County
> Median Age: 33.0 years (state: 39.6 years)
> Population under 18: 16.6% (state: 19.8%)
> Population 65 and over: 12.0% (state: 16.5%)
> Total population: 801,162
> Largest city or town in county : Boston
Michigan: Isabella County
> Median Age: 28.7 years (state: 39.8 years)
> Population under 18: 17.4% (state: 21.7%)
> Population 65 and over: 12.7% (state: 17.2%)
> Total population: 70,363
> Largest city or town in county : Mount Pleasant
Minnesota: Blue Earth County
> Median Age: 31.3 years (state: 38.1 years)
> Population under 18: 19.7% (state: 23.2%)
> Population 65 and over: 13.7% (state: 15.8%)
> Total population: 67,368
> Largest city or town in county : Mankato
Mississippi: Oktibbeha County
> Median Age: 26.1 years (state: 37.7 years)
> Population under 18: 17.5% (state: 23.7%)
> Population 65 and over: 11.4% (state: 15.9%)
> Total population: 49,593
> Largest city or town in county : Starkville
Missouri: Pulaski County
> Median Age: 27.8 years (state: 38.7 years)
> Population under 18: 21.9% (state: 22.5%)
> Population 65 and over: 8.6% (state: 16.9%)
> Total population: 52,359
> Largest city or town in county : Fort Leonard Wood
Montana: Roosevelt County
> Median Age: 30.4 years (state: 40.1 years)
> Population under 18: 33.6% (state: 21.5%)
> Population 65 and over: 11.5% (state: 18.7%)
> Total population: 11,091
> Largest city or town in county : Wolf Point
Nebraska: Thurston County
> Median Age: 28.0 years (state: 36.6 years)
> Population under 18: 35.8% (state: 24.7%)
> Population 65 and over: 12.1% (state: 15.7%)
> Total population: 7,218
> Largest city or town in county : Pender
Nevada: Elko County
> Median Age: 34.7 years (state: 38.2 years)
> Population under 18: 26.9% (state: 22.7%)
> Population 65 and over: 11.7% (state: 15.8%)
> Total population: 52,537
> Largest city or town in county : Elko
New Hampshire: Strafford County
> Median Age: 36.8 years (state: 43.0 years)
> Population under 18: 18.4% (state: 19.0%)
> Population 65 and over: 15.1% (state: 18.1%)
> Total population: 130,161
> Largest city or town in county : Dover
New Jersey: Hudson County
> Median Age: 35.3 years (state: 40.0 years)
> Population under 18: 20.4% (state: 22.0%)
> Population 65 and over: 12.0% (state: 16.2%)
> Total population: 671,923
> Largest city or town in county : Jersey City
New Mexico: De Baca County
> Median Age: 22.2 years (state: 38.1 years)
> Population under 18: 42.7% (state: 23.1%)
> Population 65 and over: 14.5% (state: 17.4%)
> Total population: 1,995
> Largest city or town in county : Fort Sumner
New York: Tompkins County
> Median Age: 31.3 years (state: 39.0 years)
> Population under 18: 14.7% (state: 20.9%)
> Population 65 and over: 14.3% (state: 16.5%)
> Total population: 102,237
> Largest city or town in county : Ithaca
North Carolina: Onslow County
> Median Age: 26.5 years (state: 38.9 years)
> Population under 18: 24.3% (state: 22.2%)
> Population 65 and over: 9.2% (state: 16.3%)
> Total population: 198,377
> Largest city or town in county : Jacksonville
North Dakota: Sioux County
> Median Age: 28.6 years (state: 35.2 years)
> Population under 18: 34.9% (state: 23.4%)
> Population 65 and over: 8.6% (state: 15.3%)
> Total population: 4,339
> Largest city or town in county : Cannon Ball
Ohio: Athens County
> Median Age: 30.0 years (state: 39.5 years)
> Population under 18: 14.5% (state: 22.2%)
> Population 65 and over: 12.9% (state: 17.0%)
> Total population: 65,945
> Largest city or town in county : Athens
Oklahoma: Payne County
> Median Age: 27.3 years (state: 36.7 years)
> Population under 18: 19.1% (state: 24.2%)
> Population 65 and over: 12.6% (state: 15.7%)
> Total population: 81,912
> Largest city or town in county : Stillwater
Oregon: Benton County
> Median Age: 33.2 years (state: 39.5 years)
> Population under 18: 16.2% (state: 20.8%)
> Population 65 and over: 16.0% (state: 17.6%)
> Total population: 92,168
> Largest city or town in county : Corvallis
Pennsylvania: Centre County
> Median Age: 32.9 years (state: 40.9 years)
> Population under 18: 15.0% (state: 20.7%)
> Population 65 and over: 14.2% (state: 18.3%)
> Total population: 162,264
> Largest city or town in county : State College
Rhode Island: Providence County
> Median Age: 37.4 years (state: 40.0 years)
> Population under 18: 20.6% (state: 19.4%)
> Population 65 and over: 15.3% (state: 17.3%)
> Total population: 636,161
> Largest city or town in county : Providence
South Carolina: Richland County
> Median Age: 33.7 years (state: 39.7 years)
> Population under 18: 21.5% (state: 21.8%)
> Population 65 and over: 12.7% (state: 17.7%)
> Total population: 414,660
> Largest city or town in county : Columbia
South Dakota: Todd County
> Median Age: 23.6 years (state: 37.2 years)
> Population under 18: 41.9% (state: 24.5%)
> Population 65 and over: 7.4% (state: 16.7%)
> Total population: 10,308
> Largest city or town in county : Rosebud
Tennessee: Montgomery County
> Median Age: 31.0 years (state: 38.8 years)
> Population under 18: 26.8% (state: 22.3%)
> Population 65 and over: 9.3% (state: 16.4%)
> Total population: 204,992
> Largest city or town in county : Clarksville
Texas: Brazos County
> Median Age: 26.8 years (state: 34.8 years)
> Population under 18: 20.6% (state: 25.8%)
> Population 65 and over: 9.2% (state: 12.5%)
> Total population: 226,370
> Largest city or town in county : College Station
Utah: Utah County
> Median Age: 25.0 years (state: 31.1 years)
> Population under 18: 33.3% (state: 29.4%)
> Population 65 and over: 7.7% (state: 11.1%)
> Total population: 621,506
> Largest city or town in county : Provo
Vermont: Chittenden County
> Median Age: 36.5 years (state: 42.8 years)
> Population under 18: 17.8% (state: 18.5%)
> Population 65 and over: 15.1% (state: 19.4%)
> Total population: 163,414
> Largest city or town in county : Burlington
Virginia: Lexington city
> Median Age: 22.2 years (state: 38.4 years)
> Population under 18: 8.1% (state: 22.0%)
> Population 65 and over: 14.3% (state: 15.4%)
> Total population: 7,205
> Largest city or town in county : Lexington
Washington: Whitman County
> Median Age: 25.2 years (state: 37.8 years)
> Population under 18: 15.0% (state: 22.0%)
> Population 65 and over: 10.7% (state: 15.4%)
> Total population: 49,577
> Largest city or town in county : Pullman
West Virginia: Monongalia County
> Median Age: 32.2 years (state: 42.7 years)
> Population under 18: 16.3% (state: 20.2%)
> Population 65 and over: 12.7% (state: 19.9%)
> Total population: 106,196
> Largest city or town in county : Morgantown
Wisconsin: Menominee County
> Median Age: 31.0 years (state: 39.6 years)
> Population under 18: 32.6% (state: 21.9%)
> Population 65 and over: 13.2% (state: 16.9%)
> Total population: 4,566
> Largest city or town in county : Legend Lake
Wyoming: Albany County
> Median Age: 28.2 years (state: 38.0 years)
> Population under 18: 16.0% (state: 23.2%)
> Population 65 and over: 11.9% (state: 16.4%)
> Total population: 38,664
> Largest city or town in county : Laramie