| | Tempe, AZ | Romeoville, IL | United States |
| Population | 178,862 | 40,099 | 329,725,481 |
| Female Population | 46.8% | 50.8% | 50.5% |
| Male Population | 53.2% | 49.2% | 49.5% |
| Median Age | 29.6 | 35.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 162,317 | 39,697 | 309,327,143 |
| Population - 2000 | 158,625 | 21,153 | 285,036,114 |
| Population - 1990 | 141,865 | 14,074 | 251,960,433 |
| Pop. 2000 to Now | 26.3% | 88.0% | 15.6% |
| Pop. 1990 to Now | 41.3% | 182.6% | 30.8% |
| space4 | | | |
| Population Density | 4,474.1 | 2,109.0 | 93.4 |
| Land Area | 40.0 | 19.0 | 3,531,905.4 |
| Water Area | 0.2 | 1.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Tempe, AZ | Romeoville, IL | United States |
| Age 0 to 4 | 4.6% | 5.8% | 5.9% |
| Age 5 to 9 | 3.5% | 5.7% | 6.1% |
| Age 10 to 14 | 3.7% | 6.4% | 6.6% |
| Age 15 to 17 | 2.5% | 5.6% | 3.9% |
| Age 18 to 20 | 10.1% | 6.3% | 4.0% |
| Age 21 to 24 | 12.7% | 6.7% | 5.2% |
| Age 25 to 34 | 22.8% | 12.8% | 13.8% |
| Age 35 to 44 | 11.5% | 13.6% | 12.9% |
| Age 45 to 54 | 8.5% | 14.9% | 12.6% |
| Age 55 to 59 | 4.7% | 6.7% | 6.7% |
| Age 60 to 64 | 5.0% | 4.6% | 6.3% |
| Age 65 to 74 | 6.2% | 6.4% | 9.6% |
| Age 75 to 84 | 3.0% | 3.2% | 4.5% |
| Age 85 and over | 1.2% | 1.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Tempe, AZ | Romeoville, IL | United States |
| White | 54.1% | 45.7% | 59.4% |
| Black | 7.1% | 11.1% | 12.2% |
| Asian | 8.6% | 5.8% | 5.6% |
| Native American | 2.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.4% | 0.0% | 0.2% |
| Other | 0.4% | 0.2% | 0.4% |
| Two or More Races | 4.3% | 3.3% | 3.2% |
| Hispanic | 23.1% | 33.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Tempe, AZ | Romeoville, IL | United States |
| Married Population | 31.7% | 50.1% | 49.8% |
| Currently Married | 30.4% | 48.8% | 48.0% |
| Married but Separated | 1.3% | 1.3% | 1.8% |
| Single Population | 68.3% | 49.9% | 50.2% |
| Never Married | 55.4% | 36.7% | 33.8% |
| Divorced | 9.9% | 8.3% | 10.8% |
| Widowed | 3.0% | 4.8% | 5.6% |
| space5 | | | |
| Household Size | 2.27 | 3.24 | 2.60 |
| Households | 73,785 | 12,047 | 124,010,992 |
| Family Households | 33,837 | 9,079 | 80,755,759 |
| Married couple, w/children | 24.4% | 40.1% | 30.5% |
| Married couple, no children | 41.0% | 38.9% | 42.9% |
| Non Family Households | 39,948 | 2,968 | 43,255,233 |
| Single householder, w/children | 16.5% | 11.4% | 15.8% |
| Single householder, no children | 18.0% | 9.5% | 10.8% |