Colorado Counties That Are Losing Younger Residents

Colorado's population has steadily risen in recent years, with the state adding an 8th Congressional District as a result — and a recent study found that Colorado is among the top dream destinations for Millennials and members of Generation Z looking to relocate. But figures from the state demographer reveal that the flow of newcomers is finally starting to slow.

This development could result in challenges across Colorado, but especially in counties whose populations have either shrunk overall or are seeing a decrease in young residents — a key indicator of economic vitality. And the latter phenomenon isn't exactly rare. According to data from the  U.S. Census Bureau, 39 of Colorado's 64 counties had fewer people under age eighteen living there in 2020 than in 2010.

The state demography office page on the Colorado Department of Local Affairs website reveals that the state's population rose by over 40,000 from 2019 to 2020, going from 5,734,932 to 5,782,902 — and the total is projected to hit 6,499,620 in 2030. But the number of Coloradans ages seventeen and under actually fell by more than 2,000 over that span — 1,255,578 in 2019 to 1,248,342 in 2020 — and is only projected to reach 1,257,273 in 2030.

Meanwhile, on February 14, Colorado demographer Elizabeth Garner told 9News that new transplants to the state added up to 14,731 in 2021, just over half of the 27,337 who moved here in 2020 and far below the 68,844 arrivals in 2015.

Stats from the 2020 census indicate that communities along Colorado's urban corridor are least likely to see such a slowdown. Each of the following eight Colorado counties experienced substantial growth in the population of residents both younger and older than eighteen from 2010 to 2020.

Adams County, Colorado
Percent Change in Population
Aged 18 and over: 22.4% (increase of 70,791 people)
Under the age of 18: 5.7% (increase of 7,178 people)

Arapahoe County, Colorado
Percent Change in Population
Aged 18 and over: 18.1% (increase of 77,001 people)
Under the age of 18: 4.1% (increase of 6,066 people)

Broomfield County, Colorado
Percent Change in Population
Aged 18 and over: 40.4% (increase of 16,679 people)
Under the age of 18: 10.5% (increase of 1,544 people)

Denver County, Colorado
Percent Change in Population
Aged 18 and over: 23.3% (increase of 109,670 people)
Under the age of 18: 4.4% (increase of 5,694 people)

Douglas County, Colorado
Percent Change in Population
Aged 18 and over: 34.0% (increase of 67,553 people)
Under the age of 18: 5.7% (increase of 4,960 people)

El Paso County, Colorado
Percent Change in Population
Aged 18 and over: 21.6% (increase of 99,124 people)
Under the age of 18: 5.5% (increase of 9,008 people)

Larimer County, Colorado
Percent Change in Population
Aged 18 and over: 22.8% (increase of 53,760 people)
Under the age of 18: 8.9% (increase of 5,676 people)

Weld County, Colorado
Percent Change in Population
Aged 18 and over: 32.6% (increase of 59,409 people)
Under the age of 18: 23.8% (increase of 16,747 people)

While two metro counties, Boulder and Jefferson, actually saw decreases in residents younger than eighteen, their gains among those older than eighteen easily made up the difference. But that wasn't the case everywhere. Ten Colorado counties, most of them rural, saw decreases in both demographic groups from 2010 to 2020. The hardest hit was Las Animas County, along the state's southern border; its largest community is Trinidad. Over the decade, the county lost 222 people over eighteen and 730 people under eighteen from a population of around 15,000.

Continue to count down the 39 Colorado counties that saw losses in their under-eighteen population from 2010 to 2020, ranked from the smallest to the largest percentage decreases.

39. Boulder County, Colorado
Percent Change in Population
Aged 18 and over: 15.9% (increase of 36,827 people)
Under the age of 18: -1.0% (decrease of 636 people)

38. La Plata County, Colorado
Percent Change in Population
Aged 18 and over: 10.9% (increase of 4,447 people)
Under the age of 18: -1.4% (decrease of 143 people)

37. Morgan County, Colorado
Percent Change in Population
Aged 18 and over: 5.5% (increase of 1,106 people)
Under the age of 18: -2.0% (decrease of 154 people)

36. Eagle County, Colorado
Percent Change in Population
Aged 18 and over: 9.8% (increase of 3,866 people)
Under the age of 18: -2.6% (decrease of 332 people)

35. Washington County, Colorado
Percent Change in Population
Aged 18 and over: 0.9% (increase of 33 people)
Under the age of 18: -2.7% (decrease of 30 people)

34. Routt County, Colorado
Percent Change in Population
Aged 18 and over: 7.8% (increase of 1,460 people)
Under the age of 18: -2.9% (decrease of 140 people)

33. Custer County, Colorado
Percent Change in Population
Aged 18 and over: 13.4% (increase of 471 people)
Under the age of 18: -3.0% (decrease of 22 people)

32. Kit Carson County, Colorado
Percent Change in Population
Aged 18 and over: -17.5% (decrease of 1,126 people)
Under the age of 18: -3.1% (decrease of 57 people)

31. Elbert County, Colorado
Percent Change in Population
Aged 18 and over: 18.4% (increase of 3,163 people)
Under the age of 18: -3.2% (decrease of 187 people)

30. Pitkin County, Colorado
Percent Change in Population
Aged 18 and over: 2.3% (increase of 332 people)
Under the age of 18: -4.1% (decrease of 122 people)

29. Jefferson County, Colorado
Percent Change in Population
Aged 18 and over: 12.9% (increase of 53,613 people)
Under the age of 18: -4.4% (decrease of 5,246 people)

28. Mesa County, Colorado
Percent Change in Population
Aged 18 and over: 9.7% (increase of 10,849 people)
Under the age of 18: -5.4% (decrease of 1,869 people)

27. Fremont County, Colorado
Percent Change in Population
Aged 18 and over: 6.7% (increase of 2,591 people)
Under the age of 18: -5.8% (decrease of 476 people)

26. Otero County, Colorado
Percent Change in Population
Aged 18 and over: 1.0% (increase of 147 people)
Under the age of 18: -6.2% (decrease of 288 people)

25. Jackson County, Colorado
Percent Change in Population
Aged 18 and over: 0.3% (increase of 3 people)
Under the age of 18: -6.9% (decrease of 18 people)

24. Gilpin County, Colorado
Percent Change in Population
Aged 18 and over: 9.7% (increase of 434 people)
Under the age of 18: -7.0% (decrease of 67 people)

23. Baca County, Colorado
Percent Change in Population
Aged 18 and over: -7.4% (decrease of 221 people)
Under the age of 18: -7.5% (decrease of 61 people)

22. Huerfano County, Colorado
Percent Change in Population
Aged 18 and over: 3.6% (increase of 199 people)
Under the age of 18: -7.6% (decrease of 90 people)

21. Mineral County, Colorado
Percent Change in Population
Aged 18 and over: 26.5% (increase of 162 people)
Under the age of 18: -8.9% (decrease of 9 people)

20. Cheyenne County, Colorado
Percent Change in Population
Aged 18 and over: -3.5% (decrease of 48 people)
Under the age of 18: -8.9% (decrease of 40 people)

19. Delta County, Colorado
Percent Change in Population
Aged 18 and over: 3.7% (increase of 892 people)
Under the age of 18: -9.5% (decrease of 648 people)

18. Logan County, Colorado
Percent Change in Population
Aged 18 and over: -4.1% (decrease of 736 people)
Under the age of 18: -9.8% (decrease of 445 people)

17. Park County, Colorado
Percent Change in Population
Aged 18 and over: 11.4% (increase of 1,497 people)
Under the age of 18: -10.1% (decrease of 313 people)

16. Montezuma County, Colorado
Percent Change in Population
Aged 18 and over: 4.8% (increase of 928 people)
Under the age of 18: -10.2% (decrease of 614 people)

15. Prowers County, Colorado
Percent Change in Population
Aged 18 and over: -2.0% (decrease of 187 people)
Under the age of 18: -10.7% (decrease of 365 people)

14. Montrose County, Colorado
Percent Change in Population
Aged 18 and over: 8.1% (increase of 2,511 people)
Under the age of 18: -10.9% (decrease of 1,108 people)

13. Moffat County, Colorado
Percent Change in Population
Aged 18 and over: -0.7% (decrease of 69 people)
Under the age of 18: -11.6% (decrease of 434 people)

12. Clear Creek County, Colorado
Percent Change in Population
Aged 18 and over: 6.6% (increase of 494 people)
Under the age of 18: -11.8% (decrease of 185 people)

11. Teller County, Colorado
Percent Change in Population
Aged 18 and over: 10.6% (increase of 1,974 people)
Under the age of 18: -12.8% (decrease of 614 people)

10. Dolores County, Colorado
Percent Change in Population
Aged 18 and over: 20.1% (increase of 322 people)
Under the age of 18: -13.0% (decrease of 60 people)

9. Grand County, Colorado
Percent Change in Population
Aged 18 and over: 10.7% (increase of 1,265 people)
Under the age of 18: -13.0% (decrease of 391 people)

8. Ouray County, Colorado
Percent Change in Population
Aged 18 and over: 14.9% (increase of 544 people)
Under the age of 18: -13.3% (decrease of 106 people)

7. Rio Grande County, Colorado
Percent Change in Population
Aged 18 and over: 0.0% (increase of 2 people)
Under the age of 18: -14.7% (decrease of 445 people)

6. Lake County, Colorado
Percent Change in Population
Aged 18 and over: 7.2% (increase of 396 people)
Under the age of 18: -14.8% (decrease of 270 people)

5. Costilla County, Colorado
Percent Change in Population
Aged 18 and over: 3.3% (increase of 91 people)
Under the age of 18: -15.8% (decrease of 116 people)

4. Conejos County, Colorado
Percent Change in Population
Aged 18 and over: -6.8% (decrease of 405 people)
Under the age of 18: -16.7% (decrease of 390 people)

3. Crowley County, Colorado
Percent Change in Population
Aged 18 and over: 5.0% (increase of 250 people)
Under the age of 18: -19.1% (decrease of 151 people)

2. Hinsdale County, Colorado
Percent Change in Population
Aged 18 and over: -2.7% (decrease of 18 people)
Under the age of 18: -22.0% (decrease of 37 people)

1. Las Animas County, Colorado
Percent Change in Population
Aged 18 and over: -1.8% (decrease of 222 people)
Under the age of 18: -22.5% (decrease of 730 people)