Colorado Counties by Population (2026)
2026 Pop.
100K
200K
300K
400K
500K
600K
700K
Top 5 Most Populous Counties
761,724
739,635
671,880
580,543
560,079
| County | 2026 Pop. ↓ | Area (mi²) | Density (/mi²) | Change (2020) |
|---|---|---|---|---|
| El Paso County | 761,724 | 2.1K | 358 | 3.82% |
| Denver County | 739,635 | 153 | 4,834 | 3.06% |
| Arapahoe County | 671,880 | 798 | 842 | 2.53% |
| Jefferson County | 580,543 | 764 | 760 | -0.44% |
| Adams County | 560,079 | 1.2K | 480 | 7.62% |
| Douglas County | 405,741 | 841 | 482 | 12.61% |
| Weld County | 385,572 | 4K | 97 | 16.33% |
| Larimer County | 380,384 | 2.6K | 147 | 5.68% |
| Boulder County | 327,635 | 726 | 451 | -1.01% |
| Pueblo County | 168,392 | 2.4K | 71 | 0.03% |
| Mesa County | 164,290 | 3.3K | 49 | 5.31% |
| Broomfield County | 79,945 | 33 | 2,423 | 7.33% |
| Garfield County | 63,128 | 2.9K | 21 | 2.16% |
| La Plata County | 56,866 | 1.7K | 34 | 2.13% |
| Eagle County | 53,947 | 1.7K | 32 | -3.07% |
| Fremont County | 50,074 | 1.5K | 33 | 2.44% |
| Montrose County | 44,495 | 2.2K | 20 | 3.9% |
| Delta County | 32,062 | 1.1K | 28 | 3.22% |
| Elbert County | 31,724 | 1.9K | 17 | 21.03% |
| Summit County | 31,391 | 608 | 52 | 0.49% |
| Morgan County | 30,296 | 1.3K | 24 | 4.18% |
| Montezuma County | 26,662 | 2K | 13 | 2.98% |
| Routt County | 25,187 | 2.4K | 11 | 1.41% |
| Teller County | 24,769 | 557 | 44 | 0.09% |
| Chaffee County | 20,866 | 1K | 21 | 7.08% |
| Logan County | 20,618 | 1.8K | 11 | -2.84% |
| Park County | 18,279 | 2.2K | 8.3 | 4.9% |
| Otero County | 17,478 | 1.3K | 14 | -6.33% |
| Gunnison County | 17,471 | 3.2K | 5.4 | 3.07% |
| Grand County | 16,709 | 1.8K | 9.1 | 6.1% |
| Alamosa County | 16,685 | 723 | 23 | 1.88% |
| Pitkin County | 16,484 | 971 | 17 | -5.06% |
| Archuleta County | 14,478 | 1.4K | 11 | 7.84% |
| Las Animas County | 14,271 | 4.8K | 3.0 | -1.52% |
| Moffat County | 12,940 | 4.7K | 2.7 | -2.46% |
| Prowers County | 11,864 | 1.6K | 7.2 | -1.23% |
| Rio Grande County | 11,031 | 912 | 12 | -4.39% |
| Yuma County | 9,919 | 2.4K | 4.2 | -0.56% |
| Clear Creek County | 8,965 | 395 | 23 | -4.2% |
| San Miguel County | 7,688 | 1.3K | 6.0 | -4.53% |
| Lake County | 7,633 | 377 | 20 | 3.02% |
| Conejos County | 7,534 | 1.3K | 5.9 | 1.03% |
| Kit Carson County | 7,111 | 2.2K | 3.3 | 0.69% |
| Huerfano County | 7,029 | 1.6K | 4.4 | 3% |
| Saguache County | 6,778 | 3.2K | 2.1 | 5.97% |
| Rio Blanco County | 6,574 | 3.2K | 2.0 | 0.8% |
| Gilpin County | 6,191 | 150 | 41 | 6.43% |
| Crowley County | 5,706 | 787 | 7.3 | -0.02% |
| Lincoln County | 5,688 | 2.6K | 2.2 | 0.39% |
| Bent County | 5,687 | 1.5K | 3.8 | 3.93% |
| Custer County | 5,613 | 739 | 7.6 | 18.82% |
| Ouray County | 5,357 | 541 | 9.9 | 9.8% |
| Washington County | 4,716 | 2.5K | 1.9 | -1.95% |
| Phillips County | 4,386 | 688 | 6.4 | -3.14% |
| Costilla County | 3,685 | 1.2K | 3.0 | 5.32% |
| Baca County | 3,308 | 2.6K | 1.3 | -4.89% |
| Dolores County | 2,480 | 1.1K | 2.3 | 6.39% |
| Sedgwick County | 2,223 | 548 | 4.1 | -7.03% |
| Cheyenne County | 1,734 | 1.8K | 0.98 | -0.69% |
| Kiowa County | 1,421 | 1.8K | 0.80 | -2.2% |
| Jackson County | 1,145 | 1.6K | 0.71 | -16.97% |
| Mineral County | 896 | 876 | 1.0 | 2.99% |
| San Juan County | 805 | 388 | 2.1 | 13.38% |
| Hinsdale County | 753 | 1.1K | 0.67 | -4.56% |
Sources
- US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
- US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
- American Community Survey (2009 - 2013)
- Census QuickFacts
- Historical Populations of States and Counties (1790 - 1990)