| PEOPLE | Manassas | Fountain Valley | United States |
| Population | 37,821 | 55,313 | 308,035,306 |
| Pop. Density | 3,828 | 6,134 | 87 |
| Pop. Change | 8.56% | 2.15% | 8.07% |
| Median Age | 32.2 | 42.6 | 37.3 |
| Households | 12,527 | 18,648 | 116,716,292 |
| Household Size | 3.02 | 2.97 | 2.58 |
| Male Population | 50.15% | 48.70% | 49.27% |
| Female Population | 49.85% | 51.30% | 50.96% |
| Married Population | 48.03% | 50.03% | 47.02% |
| Single Population | 51.97% | 49.97% | 52.98% |
| ESTIMATED TOTAL POPULATION BY AGE | | | |
| Age 0 to 4 | 8.45% | 4.62% | 6.56% |
| Age 5 to 9 | 7.78% | 5.49% | 6.61% |
| Age 10 to 14 | 7.53% | 6.58% | 6.71% |
| Age 15 to 17 | 4.66% | 4.36% | 4.21% |
| Age 18 to 20 | 2.65% | 2.74% | 2.95% |
| Age 21 to 24 | 6.95% | 5.62% | 7.01% |
| Age 25 to 34 | 16.51% | 10.55% | 13.33% |
| Age 35 to 44 | 14.54% | 13.52% | 13.33% |
| Age 45 to 49 | 14.40% | 15.74% | 14.61% |
| Age 50 to 54 | 14.40% | 15.74% | 14.61% |
| Age 55 to 59 | 9.65% | 13.22% | 11.84% |
| Age 60 to 64 | 9.65% | 13.22% | 11.84% |
| Age 65 to 74 | 4.06% | 10.35% | 7.05% |
| Age 75 to 84 | 1.97% | 5.15% | 4.24% |
| Age 85 and over | 0.86% | 2.06% | 1.78% |
| RACE | | | |
| White | 61.70% | 56.45% | 72.41% |
| Black | 13.72% | 0.92% | 12.61% |
| Asian | 4.98% | 33.30% | 4.75% |
| American Indian | 0.61% | 0.41% | 0.95% |
| Other | 18.99% | 8.91% | 9.28% |
| Hispanic | 0.35% | 19.39% | 16.35% |
| Non-Hispanic | 99.65% | 80.61% | 83.65% |
| FAMILY | | | |
| Married, w/children | 37.50% | 31.95% | 30.42% |
| Married, no children | 34.88% | 46.43% | 42.46% |
| Single, w/children | 15.74% | 7.56% | 14.39% |
| Single, no children | 11.87% | 14.06% | 12.73% |
| Divorced | 8.66% | 9.10% | 10.62% |
| Separated | 7.16% | 4.84% | 4.97% |
| Widowed | 4.44% | 5.93% | 6.14% |
| Now Married | 48.66% | 50.36% | 46.32% |
| Never Married | 31.08% | 29.77% | 31.95% |
