| | Oblong, IL | Nokomis, IL | United States |
| Population | 1,405 | 2,252 | 329,725,481 |
| Female Population | 48.5% | 52.6% | 50.5% |
| Male Population | 51.5% | 47.4% | 49.5% |
| Median Age | 35.2 | 35.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,467 | 2,252 | 309,327,143 |
| Population - 2000 | 1,580 | 2,389 | 285,036,114 |
| Population - 1990 | 1,616 | 2,534 | 251,960,433 |
| Pop. 2000 to Now | -14.1% | -13.1% | 15.6% |
| Pop. 1990 to Now | -16.0% | -18.0% | 30.8% |
| space4 | | | |
| Population Density | 1,293.7 | 1,727.0 | 93.4 |
| Land Area | 1.1 | 1.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Oblong, IL | Nokomis, IL | United States |
| Age 0 to 4 | 8.5% | 4.4% | 5.9% |
| Age 5 to 9 | 5.8% | 9.8% | 6.1% |
| Age 10 to 14 | 4.8% | 6.4% | 6.6% |
| Age 15 to 17 | 2.6% | 4.4% | 3.9% |
| Age 18 to 20 | 2.1% | 3.4% | 4.0% |
| Age 21 to 24 | 3.9% | 4.9% | 5.2% |
| Age 25 to 34 | 22.0% | 15.4% | 13.8% |
| Age 35 to 44 | 10.3% | 12.1% | 12.9% |
| Age 45 to 54 | 10.6% | 7.1% | 12.6% |
| Age 55 to 59 | 5.4% | 7.9% | 6.7% |
| Age 60 to 64 | 4.6% | 6.8% | 6.3% |
| Age 65 to 74 | 9.3% | 9.0% | 9.6% |
| Age 75 to 84 | 4.6% | 4.7% | 4.5% |
| Age 85 and over | 5.4% | 3.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Oblong, IL | Nokomis, IL | United States |
| White | 91.6% | 97.7% | 59.4% |
| Black | 1.5% | 0.1% | 12.2% |
| Asian | 0.0% | 1.5% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 6.1% | 0.4% | 3.2% |
| Hispanic | 0.8% | 0.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Oblong, IL | Nokomis, IL | United States |
| Married Population | 49.7% | 53.9% | 49.8% |
| Currently Married | 47.4% | 53.4% | 48.0% |
| Married but Separated | 2.3% | 0.5% | 1.8% |
| Single Population | 50.3% | 46.1% | 50.2% |
| Never Married | 24.0% | 23.6% | 33.8% |
| Divorced | 17.3% | 17.0% | 10.8% |
| Widowed | 8.9% | 5.5% | 5.6% |
| space5 | | | |
| Household Size | 1.93 | 2.40 | 2.60 |
| Households | 696 | 915 | 124,010,992 |
| Family Households | 425 | 533 | 80,755,759 |
| Married couple, w/children | 39.1% | 34.0% | 30.5% |
| Married couple, no children | 30.1% | 45.0% | 42.9% |
| Non Family Households | 271 | 382 | 43,255,233 |
| Single householder, w/children | 20.7% | 13.1% | 15.8% |
| Single householder, no children | 10.1% | 7.9% | 10.8% |