Ranking of Colorado Counties By Population Aged 25 years and above with an Educational attainment of Less than High School Diploma in 2021 (ACS-5Yrs)
Updated on September 3, 2025.
Based on the US Census ACS-5Yrs estimates, in 2021, the population of Colorado (aged 25 years and above) who had an educational attainment of Less than High School Diploma was 300,620. Among all Colorado counties, Denver County had the highest population (aged 25 years and above) with an educational attainment of Less than High School Diploma (51,244), followed by Adams County (50,604), and Arapahoe County (35,396).
The chart below shows the top 10 Colorado counties, and the table below shows the ranking of all Colorado counties.
You can see similar information for other educational attainments.
You can also see similar information for other states and for the United States.
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Related Topics: Colorado ACS-5Yrs Estimates, 2021 Topic List.
Data Source: US Census - ACS 5-Year Estimates.
Ranking of Colorado Counties By Population (Aged 25yrs+) with an Educational Attainment of Less than High School Diploma in 2021
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| Rank | County | Number of People |
|---|---|---|
| 1 | Denver County | 51244 |
| 2 | Adams County | 50604 |
| 3 | Arapahoe County | 35396 |
| 4 | El Paso County | 26185 |
| 5 | Weld County | 24878 |
| 6 | Jefferson County | 20549 |
| 7 | Pueblo County | 10891 |
| 8 | Boulder County | 9902 |
| 9 | Mesa County | 9126 |
| 10 | Larimer County | 8680 |
| 11 | Douglas County | 5012 |
| 12 | Garfield County | 4258 |
| 13 | Fremont County | 3916 |
| 14 | Morgan County | 3600 |
| 15 | Montrose County | 3402 |
| 16 | Eagle County | 3299 |
| 17 | Delta County | 2376 |
| 18 | Broomfield County | 1738 |
| 19 | Montezuma County | 1693 |
| 20 | Otero County | 1539 |
| 21 | Prowers County | 1374 |
| 22 | La Plata County | 1363 |
| 23 | Summit County | 1320 |
| 24 | Logan County | 1302 |
| 25 | Alamosa County | 1281 |
| 26 | Las Animas County | 1259 |
| 27 | Rio Grande County | 871 |
| 28 | Chaffee County | 855 |
| 29 | Yuma County | 819 |
| 30 | Moffat County | 717 |
| 31 | Elbert County | 677 |
| 32 | Grand County | 659 |
| 33 | Saguache County | 635 |
| 34 | Lake County | 629 |
| 35 | Routt County | 622 |
| 36 | Archuleta County | 608 |
| 37 | Bent County | 586 |
| 38 | Conejos County | 525 |
| 39 | Kit Carson County | 517 |
| 40 | Lincoln County | 474 |
| 41 | Crowley County | 462 |
| 42 | Teller County | 414 |
| 43 | Huerfano County | 404 |
| 44 | Phillips County | 377 |
| 45 | Baca County | 368 |
| 45 | Rio Blanco County | 368 |
| 46 | Park County | 353 |
| 47 | Costilla County | 342 |
| 48 | Pitkin County | 335 |
| 49 | Gilpin County | 293 |
| 50 | Washington County | 290 |
| 51 | Gunnison County | 223 |
| 52 | Clear Creek County | 201 |
| 53 | Sedgwick County | 197 |
| 54 | Jackson County | 150 |
| 55 | San Miguel County | 107 |
| 56 | Cheyenne County | 80 |
| 57 | Dolores County | 70 |
| 58 | Custer County | 63 |
| 59 | Ouray County | 55 |
| 60 | Hinsdale County | 27 |
| 60 | Kiowa County | 27 |
| 61 | San Juan County | 19 |
| 62 | Mineral County | 14 |