| | Hillside, IL | Aspen, CO | United States |
| Population | 8,286 | 7,019 | 329,725,481 |
| Female Population | 49.2% | 49.0% | 50.5% |
| Male Population | 50.8% | 51.0% | 49.5% |
| Median Age | 41.6 | 41.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 8,165 | 6,800 | 309,327,143 |
| Population - 2000 | 8,155 | 5,914 | 285,036,114 |
| Population - 1990 | 7,672 | 5,049 | 251,960,433 |
| Pop. 2000 to Now | -4.5% | 29.5% | 15.6% |
| Pop. 1990 to Now | 1.5% | 51.7% | 30.8% |
| space4 | | | |
| Population Density | 2,604.0 | 1,809.0 | 93.4 |
| Land Area | 3.2 | 3.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Hillside, IL | Aspen, CO | United States |
| Age 0 to 4 | 6.5% | 3.5% | 5.9% |
| Age 5 to 9 | 4.1% | 2.6% | 6.1% |
| Age 10 to 14 | 5.5% | 5.6% | 6.6% |
| Age 15 to 17 | 2.3% | 3.0% | 3.9% |
| Age 18 to 20 | 3.4% | 2.7% | 4.0% |
| Age 21 to 24 | 3.6% | 5.9% | 5.2% |
| Age 25 to 34 | 17.9% | 16.2% | 13.8% |
| Age 35 to 44 | 10.0% | 14.8% | 12.9% |
| Age 45 to 54 | 12.7% | 22.3% | 12.6% |
| Age 55 to 59 | 7.4% | 3.7% | 6.7% |
| Age 60 to 64 | 9.2% | 6.4% | 6.3% |
| Age 65 to 74 | 9.2% | 9.7% | 9.6% |
| Age 75 to 84 | 3.7% | 2.9% | 4.5% |
| Age 85 and over | 4.4% | 0.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Hillside, IL | Aspen, CO | United States |
| White | 19.9% | 85.2% | 59.4% |
| Black | 43.8% | 0.1% | 12.2% |
| Asian | 2.5% | 2.3% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.0% | 0.4% |
| Two or More Races | 0.1% | 2.1% | 3.2% |
| Hispanic | 33.4% | 10.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Hillside, IL | Aspen, CO | United States |
| Married Population | 42.6% | 45.4% | 49.8% |
| Currently Married | 40.8% | 45.4% | 48.0% |
| Married but Separated | 1.8% | 0.0% | 1.8% |
| Single Population | 57.4% | 54.6% | 50.2% |
| Never Married | 40.7% | 39.9% | 33.8% |
| Divorced | 11.5% | 13.3% | 10.8% |
| Widowed | 5.2% | 1.5% | 5.6% |
| space5 | | | |
| Household Size | 2.70 | 2.11 | 2.60 |
| Households | 2,987 | 3,278 | 124,010,992 |
| Family Households | 1,761 | 1,517 | 80,755,759 |
| Married couple, w/children | 29.6% | 43.6% | 30.5% |
| Married couple, no children | 39.4% | 46.3% | 42.9% |
| Non Family Households | 1,226 | 1,761 | 43,255,233 |
| Single householder, w/children | 3.7% | 8.6% | 15.8% |
| Single householder, no children | 27.3% | 1.5% | 10.8% |