| PEOPLE | Herndon | Westfield | United States |
| Population | 23,292 | 41,094 | 308,035,306 |
| Pop. Density | 5,450 | 887 | 87 |
| Pop. Change | 8.39% | 1.21% | 8.07% |
| Median Age | 32.8 | 38.1 | 37.3 |
| Households | 7,472 | 15,335 | 116,716,292 |
| Household Size | 3.12 | 2.49 | 2.58 |
| Male Population | 52.16% | 48.89% | 49.27% |
| Female Population | 47.84% | 51.11% | 50.96% |
| Married Population | 44.16% | 44.02% | 47.02% |
| Single Population | 55.84% | 55.98% | 52.98% |
| ESTIMATED TOTAL POPULATION BY AGE | | | |
| Age 0 to 4 | 9.00% | 5.35% | 6.56% |
| Age 5 to 9 | 6.63% | 5.55% | 6.61% |
| Age 10 to 14 | 5.82% | 6.22% | 6.71% |
| Age 15 to 17 | 3.64% | 4.31% | 4.21% |
| Age 18 to 20 | 1.99% | 5.25% | 2.95% |
| Age 21 to 24 | 6.63% | 9.49% | 7.01% |
| Age 25 to 34 | 20.87% | 10.39% | 13.33% |
| Age 35 to 44 | 16.34% | 12.35% | 13.33% |
| Age 45 to 49 | 14.01% | 14.88% | 14.61% |
| Age 50 to 54 | 14.01% | 14.88% | 14.61% |
| Age 55 to 59 | 9.84% | 12.55% | 11.84% |
| Age 60 to 64 | 9.84% | 12.55% | 11.84% |
| Age 65 to 74 | 3.43% | 6.95% | 7.05% |
| Age 75 to 84 | 1.35% | 4.41% | 4.24% |
| Age 85 and over | 0.46% | 2.29% | 1.78% |
| RACE | | | |
| White | 50.70% | 92.77% | 72.41% |
| Black | 9.54% | 1.61% | 12.61% |
| Asian | 17.90% | 1.30% | 4.75% |
| American Indian | 0.66% | 0.25% | 0.95% |
| Other | 21.19% | 4.07% | 9.28% |
| Hispanic | 2.44% | 0.66% | 16.35% |
| Non-Hispanic | 97.56% | 99.34% | 83.65% |
| FAMILY | | | |
| Married, w/children | 39.61% | 30.54% | 30.42% |
| Married, no children | 36.62% | 44.68% | 42.46% |
| Single, w/children | 12.15% | 13.36% | 14.39% |
| Single, no children | 11.61% | 11.42% | 12.73% |
| Divorced | 6.86% | 9.10% | 10.62% |
| Separated | 9.79% | 4.21% | 4.97% |
| Widowed | 2.97% | 5.82% | 6.14% |
| Now Married | 44.96% | 43.99% | 46.32% |
| Never Married | 35.42% | 36.88% | 31.95% |
