Colorado
People per square mile, 1990:
People per square mile, 2000:
Historic & Projected Growth
1790 to 2030
| Year | Population | Year | Population | Year | Population | ||
| 1790 | 0 | 1880 | 194,327 | 1970 | 2,209,596 | ||
| 1800 | 0 | 1890 | 413,249 | 1980 | 2,889,735 | ||
| 1810 | 0 | 1900 | 539,700 | 1990 | 3,294,394 | ||
| 1820 | 0 | 1910 | 799,024 | 2000 | 4,301,261 | ||
| 1830 | 0 | 1920 | 939,629 | 2010 | 4,831,554 | ||
| 1840 | 0 | 1930 | 1,035,791 | 2020 | 5,278,867 | ||
| 1850 | 0 | 1940 | 1,123,296 | 2030 | 5,792,357 | ||
| 1860 | 34,277 | 1950 | 1,325,089 | ||||
| 1870 | 39,864 | 1960 | 1,753,947 |
Population By County
| Census 2000 Population | Change from 1990 |
Percent Change | |
| COLORADO | 4,301,261 | 1,006,867 | 30.6 |
| Adams County | 363,857 | 98,819 | 37.3 |
| Alamosa County | 14,966 | 1,349 | 9.9 |
| Arapahoe County | 487,967 | 96,456 | 24.6 |
| Archuleta County | 9,898 | 4,553 | 85.2 |
| Baca County | 4,517 | -39 | -0.9 |
| Bent County | 5,998 | 950 | 18.8 |
| Boulder County | 291,288 | 65,949 | 29.3 |
| Chaffee County | 16,242 | 3,558 | 28.1 |
| Cheyenne County | 2,231 | -166 | -6.9 |
| Clear Creek County | 9,322 | 1,703 | 22.4 |
| Conejos County | 8,400 | 947 | 12.7 |
| Costilla County | 3,663 | 473 | 14.8 |
| Crowley County | 5,518 | 1,572 | 39.8 |
| Custer County | 3,503 | 1,577 | 81.9 |
| Delta County | 27,834 | 6,854 | 32.7 |
| Denver County | 554,636 | 87,026 | 18.6 |
| Dolores County | 1,844 | 340 | 22.6 |
| Douglas County | 175,766 | 115,375 | 191.0 |
| Eagle County | 41,659 | 19,731 | 90.0 |
| Elbert County | 19,872 | 10,226 | 106.0 |
| El Paso County | 516,929 | 119,915 | 30.2 |
| Fremont County | 46,145 | 13,872 | 43.0 |
| Garfield County | 43,791 | 13,817 | 46.1 |
| Gilpin County | 4,757 | 1,687 | 55.0 |
| Grand County | 12,442 | 4,476 | 56.2 |
| Gunnison County | 13,956 | 3,683 | 35.9 |
| Hinsdale County | 790 | 323 | 69.2 |
| Huerfano County | 7,862 | 1,853 | 30.8 |
| Jackson County | 1,577 | -28 | -1.7 |
| Jefferson County | 527,056 | 88,626 | 20.2 |
| Kiowa County | 1,622 | -66 | -3.9 |
| Kit Carson County | 8,011 | 871 | 12.2 |
| Lake County | 7,812 | 1,805 | 30.0 |
| La Plata County | 43,941 | 11,657 | 36.1 |
| Larimer County | 251,494 | 65,358 | 35.1 |
| Las Animas County | 15,207 | 1,442 | 10.5 |
| Lincoln County | 6,087 | 1,558 | 34.4 |
| Logan County | 20,504 | 2,937 | 16.7 |
| Mesa County | 116,255 | 23,110 | 24.8 |
| Mineral County | 831 | 273 | 48.9 |
| Moffat County | 13,184 | 1,827 | 16.1 |
| Montezuma County | 23,830 | 5,158 | 27.6 |
| Montrose County | 33,432 | 9,009 | 36.9 |
| Morgan County | 27,171 | 5,232 | 23.8 |
| Otero County | 20,311 | 126 | 0.6 |
| Ouray County | 3,742 | 1,447 | 63.1 |
| Park County | 14,523 | 7,349 | 102.4 |
| Phillips County | 4,480 | 291 | 6.9 |
| Pitkin County | 14,872 | 2,211 | 17.5 |
| Prowers County | 14,483 | 1,136 | 8.5 |
| Pueblo County | 141,472 | 18,421 | 15.0 |
| Rio Blanco County | 5,986 | 14 | 0.2 |
| Rio Grande County | 12,413 | 1,643 | 15.3 |
| Routt County | 19,690 | 5,602 | 39.8 |
| Saguache County | 5,917 | 1,298 | 28.1 |
| San Juan County | 558 | -187 | -25.1 |
| San Miguel County | 6,594 | 2,941 | 80.5 |
| Sedgwick County | 2,747 | 57 | 2.1 |
| Summit County | 23,548 | 10,667 | 82.8 |
| Teller County | 20,555 | 8,087 | 64.9 |
| Washington County | 4,926 | 114 | 2.4 |
| Weld County | 180,936 | 49,115 | 37.3 |
| Yuma County | 9,841 | 887 | 9.9 |
SOURCE: U.S. Bureau of the Census