| | Gahanna, OH | South Holland, IL | United States |
| Population | 35,626 | 21,524 | 329,725,481 |
| Female Population | 52.0% | 54.4% | 50.5% |
| Male Population | 48.0% | 45.6% | 49.5% |
| Median Age | 39.1 | 41.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 33,274 | 22,010 | 309,327,143 |
| Population - 2000 | 32,636 | 22,147 | 285,036,114 |
| Population - 1990 | 27,791 | 22,105 | 251,960,433 |
| Pop. 2000 to Now | 8.9% | -5.0% | 15.6% |
| Pop. 1990 to Now | 27.9% | -4.8% | 30.8% |
| space4 | | | |
| Population Density | 2,866.6 | 2,973.3 | 93.4 |
| Land Area | 12.4 | 7.2 | 3,531,905.4 |
| Water Area | 0.2 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Gahanna, OH | South Holland, IL | United States |
| Age 0 to 4 | 5.3% | 4.8% | 5.9% |
| Age 5 to 9 | 5.9% | 5.7% | 6.1% |
| Age 10 to 14 | 7.3% | 8.1% | 6.6% |
| Age 15 to 17 | 5.5% | 4.9% | 3.9% |
| Age 18 to 20 | 2.8% | 3.5% | 4.0% |
| Age 21 to 24 | 3.2% | 4.5% | 5.2% |
| Age 25 to 34 | 13.4% | 9.9% | 13.8% |
| Age 35 to 44 | 14.0% | 12.2% | 12.9% |
| Age 45 to 54 | 12.9% | 14.4% | 12.6% |
| Age 55 to 59 | 6.6% | 7.3% | 6.7% |
| Age 60 to 64 | 6.8% | 7.9% | 6.3% |
| Age 65 to 74 | 10.8% | 9.3% | 9.6% |
| Age 75 to 84 | 3.7% | 5.1% | 4.5% |
| Age 85 and over | 1.9% | 2.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Gahanna, OH | South Holland, IL | United States |
| White | 75.3% | 11.0% | 59.4% |
| Black | 12.7% | 80.9% | 12.2% |
| Asian | 3.6% | 0.5% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.0% | 0.8% | 0.4% |
| Two or More Races | 4.5% | 1.8% | 3.2% |
| Hispanic | 2.9% | 5.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Gahanna, OH | South Holland, IL | United States |
| Married Population | 57.1% | 43.3% | 49.8% |
| Currently Married | 55.1% | 41.3% | 48.0% |
| Married but Separated | 1.9% | 2.0% | 1.8% |
| Single Population | 42.9% | 56.7% | 50.2% |
| Never Married | 27.7% | 40.5% | 33.8% |
| Divorced | 9.6% | 9.1% | 10.8% |
| Widowed | 5.6% | 7.1% | 5.6% |
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| Household Size | 2.48 | 2.85 | 2.60 |
| Households | 14,304 | 7,383 | 124,010,992 |
| Family Households | 9,970 | 5,536 | 80,755,759 |
| Married couple, w/children | 32.7% | 17.3% | 30.5% |
| Married couple, no children | 45.7% | 42.6% | 42.9% |
| Non Family Households | 4,334 | 1,847 | 43,255,233 |
| Single householder, w/children | 14.0% | 24.5% | 15.8% |
| Single householder, no children | 7.6% | 15.6% | 10.8% |