| | Atlantis, FL | Altha, FL | United States |
| Population | 1,814 | 546 | 329,725,481 |
| Female Population | 51.1% | 47.6% | 50.5% |
| Male Population | 48.9% | 52.4% | 49.5% |
| Median Age | 62.7 | 33.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,997 | 504 | 309,327,143 |
| Population - 2000 | 2,005 | 506 | 285,036,114 |
| Population - 1990 | 1,653 | 497 | 251,960,433 |
| Pop. 2000 to Now | 6.1% | -4.7% | 15.6% |
| Pop. 1990 to Now | 28.7% | -3.0% | 30.8% |
| space4 | | | |
| Population Density | 1,338.8 | 408.4 | 93.4 |
| Land Area | 1.4 | 1.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Atlantis, FL | Altha, FL | United States |
| Age 0 to 4 | 1.9% | 8.6% | 5.9% |
| Age 5 to 9 | 2.7% | 12.1% | 6.1% |
| Age 10 to 14 | 2.7% | 10.3% | 6.6% |
| Age 15 to 17 | 1.4% | 7.9% | 3.9% |
| Age 18 to 20 | 2.0% | 0.0% | 4.0% |
| Age 21 to 24 | 1.3% | 4.2% | 5.2% |
| Age 25 to 34 | 6.2% | 9.2% | 13.8% |
| Age 35 to 44 | 8.4% | 9.3% | 12.9% |
| Age 45 to 54 | 13.7% | 14.5% | 12.6% |
| Age 55 to 59 | 4.1% | 1.8% | 6.7% |
| Age 60 to 64 | 9.5% | 6.4% | 6.3% |
| Age 65 to 74 | 22.9% | 7.1% | 9.6% |
| Age 75 to 84 | 15.8% | 6.2% | 4.5% |
| Age 85 and over | 7.3% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Atlantis, FL | Altha, FL | United States |
| White | 80.7% | 87.4% | 59.4% |
| Black | 4.7% | 0.0% | 12.2% |
| Asian | 4.6% | 8.2% | 5.6% |
| Native American | 0.3% | 1.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.0% | 0.4% |
| Two or More Races | 0.0% | 0.0% | 3.2% |
| Hispanic | 9.5% | 2.9% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Atlantis, FL | Altha, FL | United States |
| Married Population | 57.9% | 42.7% | 49.8% |
| Currently Married | 56.1% | 35.0% | 48.0% |
| Married but Separated | 1.8% | 7.7% | 1.8% |
| Single Population | 42.1% | 57.3% | 50.2% |
| Never Married | 19.0% | 31.3% | 33.8% |
| Divorced | 12.2% | 16.4% | 10.8% |
| Widowed | 10.9% | 9.5% | 5.6% |
| space5 | | | |
| Household Size | 2.11 | 3.03 | 2.60 |
| Households | 846 | 180 | 124,010,992 |
| Family Households | 524 | 123 | 80,755,759 |
| Married couple, w/children | 12.4% | 23.6% | 30.5% |
| Married couple, no children | 76.3% | 18.7% | 42.9% |
| Non Family Households | 322 | 57 | 43,255,233 |
| Single householder, w/children | 4.6% | 37.4% | 15.8% |
| Single householder, no children | 6.7% | 20.3% | 10.8% |