| | Athens, AL | Gallatin, TN | United States |
| Population | 25,213 | 43,306 | 329,725,481 |
| Female Population | 50.8% | 50.1% | 50.5% |
| Male Population | 49.2% | 49.9% | 49.5% |
| Median Age | 41.9 | 38.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 21,993 | 30,514 | 309,327,143 |
| Population - 2000 | 18,967 | 23,230 | 285,036,114 |
| Population - 1990 | 16,901 | 18,794 | 251,960,433 |
| Pop. 2000 to Now | 51.0% | 90.9% | 15.6% |
| Pop. 1990 to Now | 69.5% | 135.9% | 30.8% |
| space4 | | | |
| Population Density | 632.5 | 1,363.0 | 93.4 |
| Land Area | 39.9 | 31.8 | 3,531,905.4 |
| Water Area | 0.3 | 0.6 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Athens, AL | Gallatin, TN | United States |
| Age 0 to 4 | 5.7% | 5.8% | 5.9% |
| Age 5 to 9 | 5.6% | 8.0% | 6.1% |
| Age 10 to 14 | 4.8% | 6.0% | 6.6% |
| Age 15 to 17 | 3.8% | 2.9% | 3.9% |
| Age 18 to 20 | 3.4% | 3.7% | 4.0% |
| Age 21 to 24 | 3.7% | 4.4% | 5.2% |
| Age 25 to 34 | 15.2% | 14.5% | 13.8% |
| Age 35 to 44 | 11.6% | 13.1% | 12.9% |
| Age 45 to 54 | 12.0% | 13.6% | 12.6% |
| Age 55 to 59 | 8.7% | 6.5% | 6.7% |
| Age 60 to 64 | 7.0% | 5.3% | 6.3% |
| Age 65 to 74 | 10.6% | 9.0% | 9.6% |
| Age 75 to 84 | 6.1% | 5.5% | 4.5% |
| Age 85 and over | 1.8% | 1.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Athens, AL | Gallatin, TN | United States |
| White | 70.8% | 69.9% | 59.4% |
| Black | 15.1% | 13.9% | 12.2% |
| Asian | 1.8% | 2.8% | 5.6% |
| Native American | 0.5% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.2% | 0.4% |
| Two or More Races | 2.6% | 4.6% | 3.2% |
| Hispanic | 9.2% | 8.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Athens, AL | Gallatin, TN | United States |
| Married Population | 54.8% | 52.0% | 49.8% |
| Currently Married | 53.5% | 51.2% | 48.0% |
| Married but Separated | 1.2% | 0.8% | 1.8% |
| Single Population | 45.2% | 48.0% | 50.2% |
| Never Married | 26.4% | 29.0% | 33.8% |
| Divorced | 11.2% | 13.0% | 10.8% |
| Widowed | 7.6% | 6.0% | 5.6% |
| space5 | | | |
| Household Size | 2.41 | 2.47 | 2.60 |
| Households | 10,211 | 17,127 | 124,010,992 |
| Family Households | 6,882 | 11,622 | 80,755,759 |
| Married couple, w/children | 26.7% | 26.9% | 30.5% |
| Married couple, no children | 48.3% | 45.1% | 42.9% |
| Non Family Households | 3,329 | 5,505 | 43,255,233 |
| Single householder, w/children | 15.0% | 17.7% | 15.8% |
| Single householder, no children | 10.0% | 10.2% | 10.8% |