This is less than a one percent fall in Jefferson County’s population, from 582,928 in 2020 to 579,581 in 2021.
Jefferson County had the fourth largest population in Colorado in 2021.
The US Census Bureau found more than 73 percent of counties in the US saw a natural decrease in population in 2021. This is up from a 55.5 percent increase in 2020.
The Midwest suffered the most sustained population decreases, with many counties along the US East Coast and through the Rocky Mountains seeing increases.
The US population continues to grow, though at a slower rate than before.
Colorado Counties By Population Change from 2020 to 2021
| County | 2020 Estimated Population | 2021 Estimated Population | % Change in Population From Year to Year |
|---|---|---|---|
| Custer County | 4,712 | 5,045 | 7.1% |
| Mineral County | 867 | 924 | 6.6% |
| Elbert County | 26,206 | 27,128 | 3.5% |
| Ouray County | 4,869 | 5,035 | 3.4% |
| Costilla County | 3,506 | 3,625 | 3.4% |
| San Juan County | 710 | 733 | 3.2% |
| Archuleta County | 13,424 | 13,790 | 2.7% |
| Weld County | 331,358 | 340,036 | 2.6% |
| Chaffee County | 19,571 | 20,074 | 2.6% |
| Dolores County | 2,338 | 2,397 | 2.5% |
| Douglas County | 360,102 | 368,990 | 2.5% |
| Bent County | 5,635 | 5,759 | 2.2% |
| Crowley County | 5,893 | 6,012 | 2% |
| Gunnison County | 16,945 | 17,281 | 2% |
| Conejos County | 7,464 | 7,612 | 2% |
| Park County | 17,421 | 17,720 | 1.7% |
| Huerfano County | 6,810 | 6,920 | 1.6% |
| Fremont County | 48,981 | 49,661 | 1.4% |
| Saguache County | 6,383 | 6,471 | 1.4% |
| Delta County | 31,232 | 31,661 | 1.4% |
| Montezuma County | 25,858 | 26,175 | 1.2% |
| Alamosa County | 16,362 | 16,547 | 1.1% |
| La Plata County | 55,642 | 56,250 | 1.1% |
| Broomfield County | 74,513 | 75,325 | 1.1% |
| Gilpin County | 5,810 | 5,873 | 1.1% |
| Routt County | 24,839 | 25,091 | 1% |
| Washington County | 4,815 | 4,861 | 1% |
| Mesa County | 155,939 | 157,335 | 0.9% |
| Montrose County | 42,798 | 43,168 | 0.9% |
| El Paso County | 731,847 | 737,867 | 0.8% |
| Teller County | 24,726 | 24,926 | 0.8% |
| Grand County | 15,733 | 15,860 | 0.8% |
| Baca County | 3,486 | 3,514 | 0.8% |
| Larimer County | 359,686 | 362,533 | 0.8% |
| Pueblo County | 168,467 | 169,622 | 0.7% |
| Garfield County | 61,776 | 62,161 | 0.6% |
| Las Animas County | 14,564 | 14,633 | 0.5% |
| Clear Creek County | 9,404 | 9,446 | 0.4% |
| Adams County | 520,163 | 522,140 | 0.4% |
| Lincoln County | 5,669 | 5,688 | 0.3% |
| San Miguel County | 8,055 | 8,074 | 0.2% |
| Eagle County | 55,665 | 55,727 | 0.1% |
| Prowers County | 11,986 | 11,996 | 0.1% |
| Pitkin County | 17,342 | 17,348 | 0% |
| Kiowa County | 1,452 | 1,452 | 0% |
| Lake County | 7,409 | 7,407 | 0% |
| Arapahoe County | 655,112 | 654,900 | 0% |
| Logan County | 21,495 | 21,487 | 0% |
| Summit County | 30,971 | 30,941 | -0.1% |
| Morgan County | 29,065 | 29,008 | -0.2% |
| Yuma County | 9,979 | 9,941 | -0.4% |
| Boulder County | 330,811 | 329,543 | -0.4% |
| Otero County | 18,667 | 18,594 | -0.4% |
| Phillips County | 4,534 | 4,512 | -0.5% |
| Jefferson County | 582,928 | 579,581 | -0.6% |
| Moffat County | 13,267 | 13,185 | -0.6% |
| Rio Blanco County | 6,518 | 6,476 | -0.6% |
| Denver County | 717,630 | 711,463 | -0.9% |
| Jackson County | 1,376 | 1,363 | -0.9% |
| Rio Grande County | 11,538 | 11,408 | -1.1% |
| Kit Carson County | 7,064 | 6,950 | -1.6% |
| Hinsdale County | 794 | 781 | -1.6% |
| Cheyenne County | 1,736 | 1,707 | -1.7% |
| Sedgwick County | 2,390 | 2,336 | -2.3% |
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