| | Casper Mountain, WY | Leadville, CO | United States |
| Population | 870 | 2,623 | 329,725,481 |
| Female Population | 47.1% | 52.4% | 50.5% |
| Male Population | 52.9% | 47.6% | 49.5% |
| Median Age | 45.5 | 35 | 38.4 |
| space3 | | | |
| Population - 2010 | 340 | 2,554 | 309,327,143 |
| Population - 2000 | 298 | 2,821 | 285,036,114 |
| Population - 1990 | 215 | 2,629 | 251,960,433 |
| Pop. 2000 to Now | 107.1% | -1.7% | 15.6% |
| Pop. 1990 to Now | 187.0% | 5.5% | 30.8% |
| space4 | | | |
| Population Density | 84.2 | 2,378.1 | 93.4 |
| Land Area | 10.3 | 1.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Casper Mountain, WY | Leadville, CO | United States |
| Age 0 to 4 | 3.3% | 3.4% | 5.9% |
| Age 5 to 9 | 5.2% | 6.2% | 6.1% |
| Age 10 to 14 | 12.9% | 7.1% | 6.6% |
| Age 15 to 17 | 10.3% | 5.7% | 3.9% |
| Age 18 to 20 | 5.5% | 2.2% | 4.0% |
| Age 21 to 24 | 1.0% | 3.7% | 5.2% |
| Age 25 to 34 | 6.1% | 21.7% | 13.8% |
| Age 35 to 44 | 4.1% | 16.4% | 12.9% |
| Age 45 to 54 | 22.1% | 16.5% | 12.6% |
| Age 55 to 59 | 12.4% | 1.3% | 6.7% |
| Age 60 to 64 | 3.0% | 7.2% | 6.3% |
| Age 65 to 74 | 14.0% | 3.4% | 9.6% |
| Age 75 to 84 | 0.0% | 3.9% | 4.5% |
| Age 85 and over | 0.0% | 1.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Casper Mountain, WY | Leadville, CO | United States |
| White | 89.3% | 67.6% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 0.0% | 1.1% | 5.6% |
| Native American | 0.0% | 2.6% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.0% | 3.3% | 3.2% |
| Hispanic | 10.7% | 25.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Casper Mountain, WY | Leadville, CO | United States |
| Married Population | 72.7% | 34.6% | 49.8% |
| Currently Married | 70.8% | 34.5% | 48.0% |
| Married but Separated | 1.9% | 0.1% | 1.8% |
| Single Population | 27.3% | 65.4% | 50.2% |
| Never Married | 25.1% | 38.3% | 33.8% |
| Divorced | 2.2% | 25.5% | 10.8% |
| Widowed | 0.0% | 1.6% | 5.6% |
| space5 | | | |
| Household Size | 2.98 | 2.30 | 2.60 |
| Households | 292 | 1,122 | 124,010,992 |
| Family Households | 239 | 420 | 80,755,759 |
| Married couple, w/children | 31.8% | 31.7% | 30.5% |
| Married couple, no children | 68.2% | 29.8% | 42.9% |
| Non Family Households | 53 | 702 | 43,255,233 |
| Single householder, w/children | 0.0% | 28.8% | 15.8% |
| Single householder, no children | 0.0% | 9.8% | 10.8% |