| | Mableton, GA | Union City, GA | United States |
| Population | 41,632 | 26,273 | 329,725,481 |
| Female Population | 52.4% | 55.2% | 50.5% |
| Male Population | 47.7% | 44.8% | 49.5% |
| Median Age | 37.9 | 32.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 35,725 | 19,442 | 309,327,143 |
| Population - 2000 | 29,733 | 11,621 | 285,036,114 |
| Population - 1990 | 25,725 | 8,375 | 251,960,433 |
| Pop. 2000 to Now | 37.9% | 100.5% | 15.6% |
| Pop. 1990 to Now | 59.4% | 178.2% | 30.8% |
| space4 | | | |
| Population Density | 2,024.8 | 1,336.2 | 93.4 |
| Land Area | 20.6 | 19.7 | 3,531,905.4 |
| Water Area | 0.1 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Mableton, GA | Union City, GA | United States |
| Age 0 to 4 | 8.5% | 5.2% | 5.9% |
| Age 5 to 9 | 6.4% | 9.1% | 6.1% |
| Age 10 to 14 | 5.8% | 6.8% | 6.6% |
| Age 15 to 17 | 4.0% | 5.1% | 3.9% |
| Age 18 to 20 | 3.3% | 3.4% | 4.0% |
| Age 21 to 24 | 4.9% | 7.3% | 5.2% |
| Age 25 to 34 | 12.5% | 16.8% | 13.8% |
| Age 35 to 44 | 16.2% | 14.2% | 12.9% |
| Age 45 to 54 | 14.1% | 9.9% | 12.6% |
| Age 55 to 59 | 6.4% | 5.9% | 6.7% |
| Age 60 to 64 | 5.0% | 4.1% | 6.3% |
| Age 65 to 74 | 9.1% | 7.5% | 9.6% |
| Age 75 to 84 | 2.6% | 3.6% | 4.5% |
| Age 85 and over | 1.3% | 1.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Mableton, GA | Union City, GA | United States |
| White | 31.2% | 4.0% | 59.4% |
| Black | 40.5% | 89.7% | 12.2% |
| Asian | 1.8% | 0.0% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.3% | 0.9% | 0.4% |
| Two or More Races | 3.1% | 1.6% | 3.2% |
| Hispanic | 23.0% | 3.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Mableton, GA | Union City, GA | United States |
| Married Population | 54.3% | 28.3% | 49.8% |
| Currently Married | 52.2% | 24.8% | 48.0% |
| Married but Separated | 2.1% | 3.5% | 1.8% |
| Single Population | 45.7% | 71.7% | 50.2% |
| Never Married | 32.3% | 50.2% | 33.8% |
| Divorced | 10.0% | 17.4% | 10.8% |
| Widowed | 3.3% | 4.1% | 5.6% |
| space5 | | | |
| Household Size | 2.76 | 2.29 | 2.60 |
| Households | 15,093 | 11,433 | 124,010,992 |
| Family Households | 10,741 | 6,345 | 80,755,759 |
| Married couple, w/children | 31.5% | 25.5% | 30.5% |
| Married couple, no children | 40.3% | 13.6% | 42.9% |
| Non Family Households | 4,352 | 5,088 | 43,255,233 |
| Single householder, w/children | 16.4% | 30.6% | 15.8% |
| Single householder, no children | 11.8% | 30.3% | 10.8% |