| | Round Rock, AZ | Cortez, CO | United States |
| Population | 622 | 8,742 | 329,725,481 |
| Female Population | 59.5% | 51.0% | 50.5% |
| Male Population | 40.5% | 49.0% | 49.5% |
| Median Age | 29.2 | 37.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 922 | 8,483 | 309,327,143 |
| Population - 2000 | 601 | 7,977 | 285,036,114 |
| Population - 1990 | 422 | 7,284 | 251,960,433 |
| Pop. 2000 to Now | 22.1% | 9.5% | 15.6% |
| Pop. 1990 to Now | 73.9% | 19.9% | 30.8% |
| space4 | | | |
| Population Density | 43.7 | 1,380.2 | 93.4 |
| Land Area | 14.3 | 6.3 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Round Rock, AZ | Cortez, CO | United States |
| Age 0 to 4 | 8.0% | 5.6% | 5.9% |
| Age 5 to 9 | 7.7% | 7.3% | 6.1% |
| Age 10 to 14 | 16.1% | 7.3% | 6.6% |
| Age 15 to 17 | 9.0% | 4.2% | 3.9% |
| Age 18 to 20 | 6.1% | 2.4% | 4.0% |
| Age 21 to 24 | 1.6% | 6.0% | 5.2% |
| Age 25 to 34 | 6.6% | 12.6% | 13.8% |
| Age 35 to 44 | 15.3% | 10.5% | 12.9% |
| Age 45 to 54 | 9.2% | 11.5% | 12.6% |
| Age 55 to 59 | 3.4% | 6.1% | 6.7% |
| Age 60 to 64 | 4.8% | 7.0% | 6.3% |
| Age 65 to 74 | 9.8% | 12.2% | 9.6% |
| Age 75 to 84 | 2.4% | 4.2% | 4.5% |
| Age 85 and over | 0.0% | 3.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Round Rock, AZ | Cortez, CO | United States |
| White | 0.0% | 68.1% | 59.4% |
| Black | 0.0% | 1.1% | 12.2% |
| Asian | 0.0% | 1.6% | 5.6% |
| Native American | 100.0% | 3.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.9% | 0.4% |
| Two or More Races | 0.0% | 3.6% | 3.2% |
| Hispanic | 0.0% | 21.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Round Rock, AZ | Cortez, CO | United States |
| Married Population | 38.9% | 47.8% | 49.8% |
| Currently Married | 37.7% | 45.7% | 48.0% |
| Married but Separated | 1.2% | 2.1% | 1.8% |
| Single Population | 61.1% | 52.2% | 50.2% |
| Never Married | 56.8% | 28.2% | 33.8% |
| Divorced | 0.9% | 17.8% | 10.8% |
| Widowed | 3.3% | 6.2% | 5.6% |
| space5 | | | |
| Household Size | 4.12 | 2.44 | 2.60 |
| Households | 151 | 3,546 | 124,010,992 |
| Family Households | 112 | 2,199 | 80,755,759 |
| Married couple, w/children | 33.0% | 31.9% | 30.5% |
| Married couple, no children | 24.1% | 35.4% | 42.9% |
| Non Family Households | 39 | 1,347 | 43,255,233 |
| Single householder, w/children | 33.9% | 18.6% | 15.8% |
| Single householder, no children | 8.9% | 14.1% | 10.8% |