| PEOPLE | Herndon | Summerfield | United States |
| Population | 23,292 | 10,232 | 308,035,306 |
| Pop. Density | 5,450 | 385 | 87 |
| Pop. Change | 8.39% | 54.12% | 8.07% |
| Median Age | 32.8 | 42 | 37.3 |
| Households | 7,472 | 3,543 | 116,716,292 |
| Household Size | 3.12 | 2.88 | 2.58 |
| Male Population | 52.16% | 50.24% | 49.27% |
| Female Population | 47.84% | 49.76% | 50.96% |
| Married Population | 44.16% | 64.75% | 47.02% |
| Single Population | 55.84% | 35.25% | 52.98% |
| ESTIMATED TOTAL POPULATION BY AGE | | | |
| Age 0 to 4 | 9.00% | 4.72% | 6.56% |
| Age 5 to 9 | 6.63% | 8.15% | 6.61% |
| Age 10 to 14 | 5.82% | 9.77% | 6.71% |
| Age 15 to 17 | 3.64% | 6.27% | 4.21% |
| Age 18 to 20 | 1.99% | 2.43% | 2.95% |
| Age 21 to 24 | 6.63% | 3.38% | 7.01% |
| Age 25 to 34 | 20.87% | 5.36% | 13.33% |
| Age 35 to 44 | 16.34% | 15.34% | 13.33% |
| Age 45 to 49 | 14.01% | 21.52% | 14.61% |
| Age 50 to 54 | 14.01% | 21.52% | 14.61% |
| Age 55 to 59 | 9.84% | 13.54% | 11.84% |
| Age 60 to 64 | 9.84% | 13.54% | 11.84% |
| Age 65 to 74 | 3.43% | 6.08% | 7.05% |
| Age 75 to 84 | 1.35% | 2.72% | 4.24% |
| Age 85 and over | 0.46% | 0.71% | 1.78% |
| RACE | | | |
| White | 50.70% | 89.94% | 72.41% |
| Black | 9.54% | 4.42% | 12.61% |
| Asian | 17.90% | 2.24% | 4.75% |
| American Indian | 0.66% | 0.40% | 0.95% |
| Other | 21.19% | 3.00% | 9.28% |
| Hispanic | 2.44% | 0.00% | 16.35% |
| Non-Hispanic | 97.56% | 100.00% | 83.65% |
| FAMILY | | | |
| Married, w/children | 39.61% | 44.41% | 30.42% |
| Married, no children | 36.62% | 43.87% | 42.46% |
| Single, w/children | 12.15% | 6.18% | 14.39% |
| Single, no children | 11.61% | 5.54% | 12.73% |
| Divorced | 6.86% | 7.06% | 10.62% |
| Separated | 9.79% | 1.88% | 4.97% |
| Widowed | 2.97% | 5.07% | 6.14% |
| Now Married | 44.96% | 65.75% | 46.32% |
| Never Married | 35.42% | 20.24% | 31.95% |
