| | Illinois township (Sedgwick County), KS | Illinois township (Nemaha County), KS | United States |
| Population | Unlock | 361 | 329,725,481 |
| Female Population | 52.9% | Unlock | 50.5% |
| Male Population | 47.1% | Unlock | 49.5% |
| Median Age | Unlock | 43.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,863 | Unlock | 309,327,143 |
| Population - 2000 | Unlock | 453 | 285,036,114 |
| Population - 1990 | 1,553 | Unlock | 251,960,433 |
| Pop. 2000 to Now | Unlock | -2.0% | 15.6% |
| Pop. 1990 to Now | 27.6% | Unlock | 30.8% |
| space4 | | | |
| Population Density | Unlock | 10.1 | 93.4 |
| Land Area | 35.4 | Unlock | 3,531,905.4 |
| Water Area | Unlock | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Illinois township (Sedgwick County), KS | Illinois township (Nemaha County), KS | United States |
| Age 0 to 4 | 2.3% | Unlock | 5.9% |
| Age 5 to 9 | Unlock | 9.4% | 6.1% |
| Age 10 to 14 | 13.3% | Unlock | 6.6% |
| Age 15 to 17 | Unlock | 5.8% | 3.9% |
| Age 18 to 20 | 2.4% | Unlock | 4.0% |
| Age 21 to 24 | Unlock | 3.3% | 5.2% |
| Age 25 to 34 | 12.7% | Unlock | 13.8% |
| Age 35 to 44 | Unlock | 12.5% | 12.9% |
| Age 45 to 54 | 9.4% | Unlock | 12.6% |
| Age 55 to 59 | Unlock | 7.2% | 6.7% |
| Age 60 to 64 | 8.1% | Unlock | 6.3% |
| Age 65 to 74 | Unlock | 13.0% | 9.6% |
| Age 75 to 84 | 3.1% | Unlock | 4.5% |
| Age 85 and over | Unlock | 4.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Illinois township (Sedgwick County), KS | Illinois township (Nemaha County), KS | United States |
| White | 79.5% | Unlock | 59.4% |
| Black | Unlock | 0.0% | 12.2% |
| Asian | 0.0% | Unlock | 5.6% |
| Native American | Unlock | 0.6% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | Unlock | 0.2% |
| Other | Unlock | 0.0% | 0.4% |
| Two or More Races | 1.1% | Unlock | 3.2% |
| Hispanic | Unlock | 0.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Illinois township (Sedgwick County), KS | Illinois township (Nemaha County), KS | United States |
| Married Population | 66.0% | Unlock | 49.8% |
| Currently Married | Unlock | 47.3% | 48.0% |
| Married but Separated | 0.0% | Unlock | 1.8% |
| Single Population | Unlock | 52.7% | 50.2% |
| Never Married | 25.8% | Unlock | 33.8% |
| Divorced | Unlock | 19.7% | 10.8% |
| Widowed | 2.3% | Unlock | 5.6% |
| space5 | | | |
| Household Size | Unlock | 2.61 | 2.60 |
| Households | 609 | Unlock | 124,010,992 |
| Family Households | Unlock | 70 | 80,755,759 |
| Married couple, w/children | 31.1% | Unlock | 30.5% |
| Married couple, no children | Unlock | 57.1% | 42.9% |
| Non Family Households | 56 | Unlock | 43,255,233 |
| Single householder, w/children | Unlock | 8.6% | 15.8% |
| Single householder, no children | 3.8% | Unlock | 10.8% |