| | Fleming Island, FL | Memphis, TN | United States |
| Population | 29,505 | 634,139 | 329,725,481 |
| Female Population | 51.5% | 52.6% | 50.5% |
| Male Population | 48.5% | 47.4% | 49.5% |
| Median Age | 46.1 | 34.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 27,908 | 652,349 | 309,327,143 |
| Population - 2000 | 14,830 | 650,100 | 285,036,114 |
| Population - 1990 | 5,528 | 610,337 | 251,960,433 |
| Pop. 2000 to Now | 115.3% | -0.1% | 15.6% |
| Pop. 1990 to Now | 477.6% | 6.5% | 30.8% |
| space4 | | | |
| Population Density | 1,862.9 | 1,998.1 | 93.4 |
| Land Area | 15.8 | 317.4 | 3,531,905.4 |
| Water Area | 7.3 | 9.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Fleming Island, FL | Memphis, TN | United States |
| Age 0 to 4 | 3.7% | 7.4% | 5.9% |
| Age 5 to 9 | 5.9% | 6.8% | 6.1% |
| Age 10 to 14 | 5.6% | 6.9% | 6.6% |
| Age 15 to 17 | 4.7% | 3.8% | 3.9% |
| Age 18 to 20 | 4.7% | 4.0% | 4.0% |
| Age 21 to 24 | 3.7% | 6.1% | 5.2% |
| Age 25 to 34 | 8.1% | 16.1% | 13.8% |
| Age 35 to 44 | 12.2% | 12.1% | 12.9% |
| Age 45 to 54 | 15.9% | 11.3% | 12.6% |
| Age 55 to 59 | 8.0% | 5.8% | 6.7% |
| Age 60 to 64 | 7.6% | 6.2% | 6.3% |
| Age 65 to 74 | 12.6% | 8.4% | 9.6% |
| Age 75 to 84 | 5.8% | 3.7% | 4.5% |
| Age 85 and over | 1.5% | 1.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Fleming Island, FL | Memphis, TN | United States |
| White | 78.7% | 24.3% | 59.4% |
| Black | 5.1% | 64.4% | 12.2% |
| Asian | 2.4% | 1.7% | 5.6% |
| Native American | 0.1% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.5% | 0.3% | 0.4% |
| Two or More Races | 3.4% | 1.5% | 3.2% |
| Hispanic | 9.8% | 7.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Fleming Island, FL | Memphis, TN | United States |
| Married Population | 66.7% | 34.8% | 49.8% |
| Currently Married | 66.3% | 31.4% | 48.0% |
| Married but Separated | 0.4% | 3.4% | 1.8% |
| Single Population | 33.3% | 65.2% | 50.2% |
| Never Married | 20.9% | 48.1% | 33.8% |
| Divorced | 8.2% | 11.3% | 10.8% |
| Widowed | 4.2% | 5.7% | 5.6% |
| space5 | | | |
| Household Size | 2.66 | 2.48 | 2.60 |
| Households | 11,090 | 249,554 | 124,010,992 |
| Family Households | 8,957 | 137,746 | 80,755,759 |
| Married couple, w/children | 33.0% | 18.9% | 30.5% |
| Married couple, no children | 55.3% | 31.7% | 42.9% |
| Non Family Households | 2,133 | 111,808 | 43,255,233 |
| Single householder, w/children | 6.7% | 31.5% | 15.8% |
| Single householder, no children | 5.0% | 17.9% | 10.8% |