| PEOPLE | Winfield | O'Fallon | United States |
| Population | 1,404 | 28,281 | 308,035,306 |
| Pop. Density | 2,192 | 1,970 | 87 |
| Pop. Change | 53.58% | 26.66% | 8.07% |
| Median Age | 31.2 | 36.4 | 37.3 |
| Households | 525 | 10,747 | 116,716,292 |
| Household Size | 2.6 | 2.59 | 2.58 |
| Male Population | 49.86% | 48.53% | 49.27% |
| Female Population | 50.14% | 51.47% | 50.96% |
| Married Population | 45.70% | 54.54% | 47.02% |
| Single Population | 54.30% | 45.46% | 52.98% |
| ESTIMATED TOTAL POPULATION BY AGE | | | |
| Age 0 to 4 | 9.76% | 6.33% | 6.56% |
| Age 5 to 9 | 6.62% | 7.80% | 6.61% |
| Age 10 to 14 | 7.34% | 8.17% | 6.71% |
| Age 15 to 17 | 4.70% | 5.18% | 4.21% |
| Age 18 to 20 | 2.42% | 2.45% | 2.95% |
| Age 21 to 24 | 6.41% | 5.63% | 7.01% |
| Age 25 to 34 | 20.01% | 12.46% | 13.33% |
| Age 35 to 44 | 13.82% | 15.43% | 13.33% |
| Age 45 to 49 | 12.61% | 16.52% | 14.61% |
| Age 50 to 54 | 12.61% | 16.52% | 14.61% |
| Age 55 to 59 | 7.76% | 11.00% | 11.84% |
| Age 60 to 64 | 7.76% | 11.00% | 11.84% |
| Age 65 to 74 | 5.20% | 5.27% | 7.05% |
| Age 75 to 84 | 2.78% | 2.87% | 4.24% |
| Age 85 and over | 0.57% | 0.89% | 1.78% |
| RACE | | | |
| White | 97.01% | 77.34% | 72.41% |
| Black | 0.43% | 15.57% | 12.61% |
| Asian | 0.28% | 2.78% | 4.75% |
| American Indian | 0.00% | 0.24% | 0.95% |
| Other | 2.28% | 4.07% | 9.28% |
| Hispanic | 1.20% | 1.14% | 16.35% |
| Non-Hispanic | 98.80% | 98.86% | 83.65% |
| FAMILY | | | |
| Married, w/children | 37.22% | 37.31% | 30.42% |
| Married, no children | 31.39% | 40.02% | 42.46% |
| Single, w/children | 20.28% | 13.36% | 14.39% |
| Single, no children | 11.11% | 9.30% | 12.73% |
| Divorced | 14.07% | 9.57% | 10.62% |
| Separated | 7.78% | 3.19% | 4.97% |
| Widowed | 6.05% | 4.12% | 6.14% |
| Now Married | 45.43% | 54.73% | 46.32% |
| Never Married | 26.67% | 28.38% | 31.95% |
