| | Mukilteo, WA | Riverdale, GA | United States |
| Population | 21,409 | 15,013 | 329,725,481 |
| Female Population | 51.4% | 49.1% | 50.5% |
| Male Population | 48.6% | 50.9% | 49.5% |
| Median Age | 44.6 | 35 | 38.4 |
| space3 | | | |
| Population - 2010 | 20,286 | 14,306 | 309,327,143 |
| Population - 2000 | 18,019 | 12,478 | 285,036,114 |
| Population - 1990 | 7,007 | 9,359 | 251,960,433 |
| Pop. 2000 to Now | 18.5% | 24.4% | 15.6% |
| Pop. 1990 to Now | 204.7% | 65.8% | 30.8% |
| space4 | | | |
| Population Density | 3,419.4 | 3,397.4 | 93.4 |
| Land Area | 6.3 | 4.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Mukilteo, WA | Riverdale, GA | United States |
| Age 0 to 4 | 6.1% | 7.5% | 5.9% |
| Age 5 to 9 | 4.9% | 7.4% | 6.1% |
| Age 10 to 14 | 6.4% | 7.1% | 6.6% |
| Age 15 to 17 | 4.4% | 3.9% | 3.9% |
| Age 18 to 20 | 3.2% | 2.8% | 4.0% |
| Age 21 to 24 | 4.9% | 6.5% | 5.2% |
| Age 25 to 34 | 8.5% | 14.9% | 13.8% |
| Age 35 to 44 | 12.5% | 10.8% | 12.9% |
| Age 45 to 54 | 12.5% | 13.1% | 12.6% |
| Age 55 to 59 | 7.7% | 8.3% | 6.7% |
| Age 60 to 64 | 11.0% | 7.5% | 6.3% |
| Age 65 to 74 | 11.7% | 7.0% | 9.6% |
| Age 75 to 84 | 4.4% | 2.1% | 4.5% |
| Age 85 and over | 1.8% | 1.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Mukilteo, WA | Riverdale, GA | United States |
| White | 61.2% | 5.3% | 59.4% |
| Black | 1.3% | 81.7% | 12.2% |
| Asian | 21.3% | 6.7% | 5.6% |
| Native American | 0.2% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.3% | 0.0% | 0.2% |
| Other | 0.4% | 0.2% | 0.4% |
| Two or More Races | 8.8% | 1.5% | 3.2% |
| Hispanic | 6.4% | 4.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Mukilteo, WA | Riverdale, GA | United States |
| Married Population | 58.3% | 42.0% | 49.8% |
| Currently Married | 56.9% | 37.9% | 48.0% |
| Married but Separated | 1.4% | 4.1% | 1.8% |
| Single Population | 41.7% | 58.0% | 50.2% |
| Never Married | 25.6% | 40.2% | 33.8% |
| Divorced | 11.9% | 12.6% | 10.8% |
| Widowed | 4.2% | 5.2% | 5.6% |
| space5 | | | |
| Household Size | 2.57 | 2.65 | 2.60 |
| Households | 8,304 | 5,610 | 124,010,992 |
| Family Households | 5,850 | 3,604 | 80,755,759 |
| Married couple, w/children | 32.1% | 20.7% | 30.5% |
| Married couple, no children | 49.3% | 31.1% | 42.9% |
| Non Family Households | 2,454 | 2,006 | 43,255,233 |
| Single householder, w/children | 9.2% | 24.3% | 15.8% |
| Single householder, no children | 9.4% | 23.9% | 10.8% |