More than half of all Americans are currently under 38 years of age. By 2060, however, the majority will be at least 43-years-old, according to Census Bureau projections. Though the United States as a whole is aging rapidly, there are parts of the country where the number of young people is a defining demographic characteristic.
The increasingly aging population is largely the product of a falling birth rate and long-term improvements in life expectancy. Despite this trend, almost every state has at least one county where the median age is far lower than typical. 24/7 Wall St. reviewed median age by county to identify the youngest county in every state. These counties are often urban and include independent cities in Maryland and Virginia that effectively function as counties.
Click here to see the youngest county in every state.
Click here to see our methodology.
Many of the counties on this list are home to large colleges and universities. As the vast majority of the 19.9 million college and university students in the United States are under 25 years old, the presence of a post-secondary institution can reduce the median age of any county. Story County, Iowa, home to Iowa State University; Oktibbeha County, Mississippi, home to Mississippi State University; and Riley County, Kansas, where Kansas State University is located each rank as the youngest county in its state. In these and several other counties on this list, more than one in every four residents are enrolled in college or graduate school.
Some counties on this list skew younger due to a growing number of new families. In the youngest counties in Alaska, Idaho, North Dakota, South Dakota, and Utah, more than one in every 10 residents are under age 5. New families can also drive population growth, and the vast majority of counties on this list are larger now than they were five years ago. In some states, including New Hampshire, New Jersey, and Rhode Island, the youngest county is also the state’s fastest growing county.
Just because a county has the youngest population in the state does not necessarily mean it is younger than the United States as a whole. In both Connecticut and Maine, the median age in the youngest county is higher than the 37.8-year national median. Both Connecticut and Maine rank among the oldest states in the country, with median ages of 40.8 years and 44.3 years respectively.
1. Alabama: Lee County
> Median age: 31.0 years (county), 38.7 years (state)
> Pop. under 18: 21.6% (county), 22.7% (state)
> Population: 156,597
> Life expectancy: 76.5 years
> County seat: Opelika
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2. Alaska: Kusilvak Census Area
> Median age: 24.0 years (borough), 33.9 years (state)
> Pop. under 18: 39.7% (borough), 25.2% (state)
> Population: 8,129
> Life expectancy: 70.8 years
> Largest city: Hooper Bay
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3. Arizona: Coconino County
> Median age: 30.6 years (county), 37.2 years (state)
> Pop. under 18: 21.5% (county), 23.8% (state)
> Population: 138,639
> Life expectancy: 79.4 years
> County seat: Flagstaff
4. Arkansas: Washington County
> Median age: 31.5 years (county), 37.9 years (state)
> Pop. under 18: 24.9% (county), 23.7% (state)
> Population: 223,683
> Life expectancy: 78.1 years
> County seat: Fayetteville
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5. California: Tulare County
> Median age: 30.6 years (county), 36.1 years (state)
> Pop. under 18: 31.4% (county), 23.4% (state)
> Population: 458,809
> Life expectancy: 78.3 years
> County seat: Visalia
6. Colorado: Alamosa County
> Median age: 30.3 years (county), 36.5 years (state)
> Pop. under 18: 24.3% (county), 23% (state)
> Population: 16,345
> Life expectancy: 77.4 years
> County seat: Alamosa
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7. Connecticut: Tolland County
> Median age: 37.9 years (county), 40.8 years (state)
> Pop. under 18: 18.1% (county), 21.2% (state)
> Population: 151,596
> Life expectancy: 81.6 years
> Largest city: Vernon
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8. Delaware: Kent County
> Median age: 37.3 years (county), 39.8 years (state)
> Pop. under 18: 23.4% (county), 21.6% (state)
> Population: 173,145
> Life expectancy: 77.5 years
> County seat: Dover
9. Florida: Leon County
> Median age: 30.5 years (county), 41.8 years (state)
> Pop. under 18: 18.8% (county), 20.3% (state)
> Population: 285,890
> Life expectancy: 79.4 years
> County seat: Tallahassee
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10. Georgia: Chattahoochee County
> Median age: 23.7 years (county), 36.4 years (state)
> Pop. under 18: 22.3% (county), 24.5% (state)
> Population: 11,096
> Life expectancy: 77.1 years
> County seat: Cusseta
11. Hawaii: Honolulu County
> Median age: 37.6 years (county), 38.8 years (state)
> Pop. under 18: 21.4% (county), 21.6% (state)
> Population: 990,060
> Life expectancy: 81.4 years
> County seat: Honolulu
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12. Idaho: Madison County
> Median age: 23.5 years (county), 35.9 years (state)
> Pop. under 18: 27.1% (county), 26.2% (state)
> Population: 38,241
> Life expectancy: 81.1 years
> County seat: Rexburg
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13. Illinois: Champaign County
> Median age: 29.7 years (county), 37.7 years (state)
> Pop. under 18: 19.0% (county), 23% (state)
> Population: 207,946
> Life expectancy: 80.3 years
> County seat: Urbana
14. Indiana: Tippecanoe County
> Median age: 28.1 years (county), 37.5 years (state)
> Pop. under 18: 20.7% (county), 23.9% (state)
> Population: 186,081
> Life expectancy: 79.1 years
> County seat: Lafayette
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15. Iowa: Story County
> Median age: 25.9 years (county), 38.1 years (state)
> Pop. under 18: 16.9% (county), 23.4% (state)
> Population: 95,888
> Life expectancy: 82.1 years
> County seat: Nevada
16. Kansas: Riley County
> Median age: 24.9 years (county), 36.3 years (state)
> Pop. under 18: 16.9% (county), 24.7% (state)
> Population: 75,696
> Life expectancy: 81.5 years
> County seat: Manhattan
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17. Kentucky: Christian County
> Median age: 28.4 years (county), 38.6 years (state)
> Pop. under 18: 27.6% (county), 22.9% (state)
> Population: 72,438
> Life expectancy: 75.6 years
> County seat: Hopkinsville
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18. Louisiana: Lincoln Parish
> Median age: 27.6 years (parish), 36.4 years (state)
> Pop. under 18: 20.2% (parish), 23.9% (state)
> Population: 47,536
> Life expectancy: 77.4 years
> Parish seat: Ruston
19. Maine: Androscoggin County
> Median age: 40.7 years (county), 44.3 years (state)
> Pop. under 18: 21.9% (county), 19.3% (state)
> Population: 107,317
> Life expectancy: 78.3 years
> County seat: Auburn
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20. Maryland: Baltimore
> Median age: 35.0 years (county), 38.5 years (state)
> Pop. under 18: 21.0% (county), 22.5% (state)
> Population: 619,796
> Life expectancy: 72.1 years
> County seat: N/A
21. Massachusetts: Suffolk County
> Median age: 32.6 years (county), 39.4 years (state)
> Pop. under 18: 17.0% (county), 20.4% (state)
> Population: 780,685
> Life expectancy: 79.9 years
> County seat: Boston
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22. Michigan: Isabella County
> Median age: 27.4 years (county), 39.6 years (state)
> Pop. under 18: 17.4% (county), 22.3% (state)
> Population: 70,572
> Life expectancy: 79.1 years
> County seat: Mount Pleasant
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23. Minnesota: Blue Earth County
> Median age: 30.6 years (county), 37.9 years (state)
> Pop. under 18: 19.7% (county), 23.4% (state)
> Population: 65,767
> Life expectancy: 81.0 years
> County seat: Mankato
24. Mississippi: Oktibbeha County
> Median age: 25.4 years (county), 36.9 years (state)
> Pop. under 18: 17.5% (county), 24.3% (state)
> Population: 49,392
> Life expectancy: 77.9 years
> County seat: Starkville
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25. Missouri: Adair County
> Median age: 27.3 years (county), 38.4 years (state)
> Pop. under 18: 18.0% (county), 22.9% (state)
> Population: 25,437
> Life expectancy: 78.0 years
> County seat: Kirksville
26. Montana: Big Horn County
> Median age: 29.9 years (county), 39.8 years (state)
> Pop. under 18: 33.6% (county), 22% (state)
> Population: 13,290
> Life expectancy: 73.6 years
> County seat: Hardin
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27. Nebraska: Thurston County
> Median age: 28.1 years (county), 36.3 years (state)
> Pop. under 18: 35.6% (county), 24.8% (state)
> Population: 7,055
> Life expectancy: 73.9 years
> County seat: Pender
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28. Nevada: Elko County
> Median age: 34.1 years (county), 37.7 years (state)
> Pop. under 18: 27.7% (county), 23.2% (state)
> Population: 52,377
> Life expectancy: 78.3 years
> County seat: Elko
29. New Hampshire: Strafford County
> Median age: 37.0 years (county), 42.7 years (state)
> Pop. under 18: 19.3% (county), 19.8% (state)
> Population: 126,552
> Life expectancy: 79.5 years
> County seat: Dover
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30. New Jersey: Hudson County
> Median age: 34.9 years (county), 39.6 years (state)
> Pop. under 18: 20.4% (county), 22.3% (state)
> Population: 679,756
> Life expectancy: 80.3 years
> County seat: Jersey City
31. New Mexico: Roosevelt County
> Median age: 29.7 years (county), 37.3 years (state)
> Pop. under 18: 24.6% (county), 23.9% (state)
> Population: 19,313
> Life expectancy: 77.9 years
> County seat: Portales
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32. New York: Tompkins County
> Median age: 30.4 years (county), 38.4 years (state)
> Pop. under 18: 15.2% (county), 21.2% (state)
> Population: 104,415
> Life expectancy: 81.2 years
> County seat: Ithaca
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33. North Carolina: Onslow County
> Median age: 26.0 years (county), 38.4 years (state)
> Pop. under 18: 24.5% (county), 22.8% (state)
> Population: 192,685
> Life expectancy: 77.6 years
> County seat: Jacksonville
34. North Dakota: Sioux County
> Median age: 26.9 years (county), 35.1 years (state)
> Pop. under 18: 37.5% (county), 22.9% (state)
> Population: 4,420
> Life expectancy: 68.6 years
> County seat: Fort Yates
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35. Ohio: Athens County
> Median age: 28.6 years (county), 39.3 years (state)
> Pop. under 18: 15.0% (county), 22.6% (state)
> Population: 65,563
> Life expectancy: 76.9 years
> County seat: Athens
36. Oklahoma: Payne County
> Median age: 27.2 years (county), 36.3 years (state)
> Pop. under 18: 19.4% (county), 24.5% (state)
> Population: 80,634
> Life expectancy: 78.4 years
> County seat: Stillwater
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37. Oregon: Benton County
> Median age: 32.8 years (county), 39.2 years (state)
> Pop. under 18: 16.7% (county), 21.5% (state)
> Population: 88,249
> Life expectancy: 82.1 years
> County seat: Corvallis
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38. Pennsylvania: Centre County
> Median age: 31.3 years (county), 40.7 years (state)
> Pop. under 18: 15.3% (county), 21% (state)
> Population: 160,646
> Life expectancy: 81.9 years
> County seat: Bellefonte
39. Rhode Island: Providence County
> Median age: 37.3 years (county), 39.9 years (state)
> Pop. under 18: 20.9% (county), 19.9% (state)
> Population: 633,704
> Life expectancy: 79.3 years
> Largest city: Providence
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40. South Carolina: Richland County
> Median age: 33.0 years (county), 39.0 years (state)
> Pop. under 18: 21.8% (county), 22.3% (state)
> Population: 404,869
> Life expectancy: 77.4 years
> County seat: Columbia
41. South Dakota: Todd County
> Median age: 24.4 years (county), 36.8 years (state)
> Pop. under 18: 40.1% (county), 24.7% (state)
> Population: 10,016
> Life expectancy: 68.5 years
> County seat: Winner
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42. Tennessee: Montgomery County
> Median age: 30.5 years (county), 38.6 years (state)
> Pop. under 18: 27.0% (county), 22.7% (state)
> Population: 192,120
> Life expectancy: 76.7 years
> County seat: Clarksville
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43. Texas: Brazos County
> Median age: 25.8 years (county), 34.3 years (state)
> Pop. under 18: 20.6% (county), 26.3% (state)
> Population: 214,231
> Life expectancy: 79.9 years
> County seat: Bryan
44. Utah: Utah County
> Median age: 24.5 years (county), 30.5 years (state)
> Pop. under 18: 34.5% (county), 30.4% (state)
> Population: 576,496
> Life expectancy: 80.8 years
> County seat: Provo
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45. Vermont: Chittenden County
> Median age: 36.6 years (county), 42.8 years (state)
> Pop. under 18: 18.4% (county), 19.2% (state)
> Population: 160,985
> Life expectancy: 81.4 years
> County seat: Burlington
46. Virginia: Lexington
> Median age: 21.6 years (county), 38.0 years (state)
> Pop. under 18: 7.6% (county), 22.3% (state)
> Population: 7,113
> Life expectancy: 80.3 years
> County seat: N/A
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47. Washington: Whitman County
> Median age: 24.5 years (county), 37.6 years (state)
> Pop. under 18: 15.1% (county), 22.5% (state)
> Population: 47,794
> Life expectancy: 81.4 years
> County seat: Colfax
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48. West Virginia: Monongalia County
> Median age: 30.9 years (county), 42.2 years (state)
> Pop. under 18: 16.3% (county), 20.5% (state)
> Population: 103,715
> Life expectancy: 79.2 years
> County seat: Morgantown
49. Wisconsin: Menominee County
> Median age: 31.4 years (county), 39.2 years (state)
> Pop. under 18: 32.4% (county), 22.5% (state)
> Population: 4,506
> Life expectancy: 72.8 years
> County seat: Keshena
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50. Wyoming: Albany County
> Median age: 27.1 years (county), 37.0 years (state)
> Pop. under 18: 16.4% (county), 23.7% (state)
> Population: 37,944
> Life expectancy: 80.5 years
> County seat: Laramie
Methodology:
To identify the youngest county in each state, 24/7 Wall St. reviewed the median age of each U.S. county from the U.S. Census Bureau’s 2017 American Community Survey. Data on the share of residents under 18 years, the share under 5 years, and population changes also came from the ACS. In Alaska, county equivalents are referred to as boroughs or census areas, and in Louisiana, parishes are county equivalents. In counties without a county seat, the most populous city is listed. In our analysis, we included independent cities, which the Census categorizes alongside counties. In counties without a county seat, the most populous city is listed. We did not list a county seat of most populous city for independent cities.
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