| | Sheldon, IL | Pontiac, IL | United States |
| Population | 1,276 | 11,766 | 329,725,481 |
| Female Population | 48.8% | 46.9% | 50.5% |
| Male Population | 51.2% | 53.2% | 49.5% |
| Median Age | 46.1 | 39.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,064 | 11,911 | 309,327,143 |
| Population - 2000 | 1,232 | 11,864 | 285,036,114 |
| Population - 1990 | 1,109 | 11,428 | 251,960,433 |
| Pop. 2000 to Now | -24.1% | -5.8% | 15.6% |
| Pop. 1990 to Now | -15.7% | -2.2% | 30.8% |
| space4 | | | |
| Population Density | 1,701.3 | 1,453.0 | 93.4 |
| Land Area | 0.8 | 8.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Sheldon, IL | Pontiac, IL | United States |
| Age 0 to 4 | 6.5% | 5.2% | 5.9% |
| Age 5 to 9 | 4.5% | 4.7% | 6.1% |
| Age 10 to 14 | 4.7% | 6.8% | 6.6% |
| Age 15 to 17 | 4.2% | 3.6% | 3.9% |
| Age 18 to 20 | 4.2% | 2.6% | 4.0% |
| Age 21 to 24 | 6.3% | 4.8% | 5.2% |
| Age 25 to 34 | 10.9% | 15.5% | 13.8% |
| Age 35 to 44 | 7.4% | 13.6% | 12.9% |
| Age 45 to 54 | 19.4% | 11.3% | 12.6% |
| Age 55 to 59 | 7.8% | 7.1% | 6.7% |
| Age 60 to 64 | 8.5% | 7.2% | 6.3% |
| Age 65 to 74 | 6.4% | 9.3% | 9.6% |
| Age 75 to 84 | 4.4% | 4.9% | 4.5% |
| Age 85 and over | 4.7% | 3.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Sheldon, IL | Pontiac, IL | United States |
| White | 94.2% | 81.8% | 59.4% |
| Black | 1.3% | 8.5% | 12.2% |
| Asian | 0.0% | 1.3% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 4.0% | 2.9% | 3.2% |
| Hispanic | 0.5% | 5.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Sheldon, IL | Pontiac, IL | United States |
| Married Population | 37.4% | 41.2% | 49.8% |
| Currently Married | 37.2% | 39.3% | 48.0% |
| Married but Separated | 0.2% | 1.9% | 1.8% |
| Single Population | 62.6% | 58.8% | 50.2% |
| Never Married | 27.4% | 35.3% | 33.8% |
| Divorced | 26.4% | 15.3% | 10.8% |
| Widowed | 8.8% | 8.2% | 5.6% |
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| Household Size | 2.20 | 2.20 | 2.60 |
| Households | 569 | 4,522 | 124,010,992 |
| Family Households | 338 | 2,615 | 80,755,759 |
| Married couple, w/children | 28.1% | 24.2% | 30.5% |
| Married couple, no children | 32.0% | 42.1% | 42.9% |
| Non Family Households | 231 | 1,907 | 43,255,233 |
| Single householder, w/children | 15.4% | 26.4% | 15.8% |
| Single householder, no children | 24.6% | 7.3% | 10.8% |