| | Union, OH | Springfield, OH | United States |
| Population | 6,832 | 58,992 | 329,725,481 |
| Female Population | 49.7% | 52.7% | 50.5% |
| Male Population | 50.3% | 47.3% | 49.5% |
| Median Age | 37.6 | 36.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 6,443 | 60,531 | 309,327,143 |
| Population - 2000 | 5,574 | 65,358 | 285,036,114 |
| Population - 1990 | 5,501 | 70,487 | 251,960,433 |
| Pop. 2000 to Now | 24.0% | -10.6% | 15.6% |
| Pop. 1990 to Now | 25.6% | -17.1% | 30.8% |
| space4 | | | |
| Population Density | 800.2 | 2,291.3 | 93.4 |
| Land Area | 8.5 | 25.7 | 3,531,905.4 |
| Water Area | 0.1 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Union, OH | Springfield, OH | United States |
| Age 0 to 4 | 4.0% | 7.0% | 5.9% |
| Age 5 to 9 | 8.3% | 6.5% | 6.1% |
| Age 10 to 14 | 10.6% | 6.7% | 6.6% |
| Age 15 to 17 | 3.9% | 4.0% | 3.9% |
| Age 18 to 20 | 1.6% | 5.4% | 4.0% |
| Age 21 to 24 | 2.6% | 6.1% | 5.2% |
| Age 25 to 34 | 11.0% | 12.8% | 13.8% |
| Age 35 to 44 | 15.1% | 10.5% | 12.9% |
| Age 45 to 54 | 11.4% | 11.5% | 12.6% |
| Age 55 to 59 | 7.9% | 6.5% | 6.7% |
| Age 60 to 64 | 4.6% | 6.1% | 6.3% |
| Age 65 to 74 | 10.3% | 9.6% | 9.6% |
| Age 75 to 84 | 7.0% | 4.6% | 4.5% |
| Age 85 and over | 1.8% | 2.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Union, OH | Springfield, OH | United States |
| White | 93.0% | 70.6% | 59.4% |
| Black | 2.6% | 17.4% | 12.2% |
| Asian | 0.0% | 0.8% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 2.9% | 6.0% | 3.2% |
| Hispanic | 1.5% | 4.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Union, OH | Springfield, OH | United States |
| Married Population | 57.4% | 37.0% | 49.8% |
| Currently Married | 57.1% | 34.4% | 48.0% |
| Married but Separated | 0.3% | 2.6% | 1.8% |
| Single Population | 42.6% | 63.0% | 50.2% |
| Never Married | 23.9% | 39.9% | 33.8% |
| Divorced | 10.8% | 14.5% | 10.8% |
| Widowed | 8.0% | 8.6% | 5.6% |
| space5 | | | |
| Household Size | 2.52 | 2.35 | 2.60 |
| Households | 2,708 | 24,001 | 124,010,992 |
| Family Households | 1,751 | 13,606 | 80,755,759 |
| Married couple, w/children | 41.2% | 22.1% | 30.5% |
| Married couple, no children | 42.9% | 33.3% | 42.9% |
| Non Family Households | 957 | 10,395 | 43,255,233 |
| Single householder, w/children | 12.7% | 31.7% | 15.8% |
| Single householder, no children | 3.2% | 12.8% | 10.8% |