| PEOPLE | Plainfield | Eureka | United States |
| Population | 39,581 | 27,191 | 308,035,306 |
| Pop. Density | 1,704 | 2,898 | 87 |
| Pop. Change | 166.29% | 5.27% | 8.07% |
| Median Age | 33.6 | 36.3 | 37.3 |
| Households | 11,920 | 11,150 | 116,716,292 |
| Household Size | 3.29 | 2.28 | 2.58 |
| Male Population | 49.60% | 51.45% | 49.27% |
| Female Population | 50.40% | 48.55% | 50.96% |
| Married Population | 64.53% | 35.27% | 47.02% |
| Single Population | 35.47% | 64.73% | 52.98% |
| ESTIMATED TOTAL POPULATION BY AGE | | | |
| Age 0 to 4 | 8.78% | 6.06% | 6.56% |
| Age 5 to 9 | 10.95% | 5.32% | 6.61% |
| Age 10 to 14 | 10.34% | 5.03% | 6.71% |
| Age 15 to 17 | 5.13% | 3.56% | 4.21% |
| Age 18 to 20 | 2.29% | 2.69% | 2.95% |
| Age 21 to 24 | 3.70% | 8.72% | 7.01% |
| Age 25 to 34 | 10.71% | 16.89% | 13.33% |
| Age 35 to 44 | 21.13% | 12.61% | 13.33% |
| Age 45 to 49 | 14.14% | 14.03% | 14.61% |
| Age 50 to 54 | 14.14% | 14.03% | 14.61% |
| Age 55 to 59 | 7.58% | 13.27% | 11.84% |
| Age 60 to 64 | 7.58% | 13.27% | 11.84% |
| Age 65 to 74 | 3.21% | 6.29% | 7.05% |
| Age 75 to 84 | 1.35% | 3.76% | 4.24% |
| Age 85 and over | 0.69% | 1.78% | 1.78% |
| RACE | | | |
| White | 81.72% | 79.31% | 72.41% |
| Black | 5.56% | 1.89% | 12.61% |
| Asian | 7.62% | 4.24% | 4.75% |
| American Indian | 0.22% | 3.72% | 0.95% |
| Other | 4.87% | 10.84% | 9.28% |
| Hispanic | 1.47% | 74.98% | 16.35% |
| Non-Hispanic | 98.53% | 25.02% | 83.65% |
| FAMILY | | | |
| Married, w/children | 57.07% | 22.55% | 30.42% |
| Married, no children | 30.00% | 39.66% | 42.46% |
| Single, w/children | 7.95% | 21.55% | 14.39% |
| Single, no children | 4.98% | 16.24% | 12.73% |
| Divorced | 5.01% | 14.72% | 10.62% |
| Separated | 1.89% | 6.41% | 4.97% |
| Widowed | 2.88% | 6.66% | 6.14% |
| Now Married | 65.54% | 34.93% | 46.32% |
| Never Married | 24.68% | 37.28% | 31.95% |
