| | Lely, FL | Big Pine Key, FL | United States |
| Population | 3,530 | 4,752 | 329,725,481 |
| Female Population | 54.9% | 47.2% | 50.5% |
| Male Population | 45.1% | 52.8% | 49.5% |
| Median Age | 66 | 52.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,624 | 3,747 | 309,327,143 |
| Population - 2000 | 3,857 | 5,032 | 285,036,114 |
| Population - 1990 | 3,014 | 4,206 | 251,960,433 |
| Pop. 2000 to Now | 8.9% | 2.2% | 15.6% |
| Pop. 1990 to Now | 39.4% | 22.2% | 30.8% |
| space4 | | | |
| Population Density | 2,572.9 | 465.7 | 93.4 |
| Land Area | 1.4 | 10.2 | 3,531,905.4 |
| Water Area | 0.1 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Lely, FL | Big Pine Key, FL | United States |
| Age 0 to 4 | 1.5% | 5.5% | 5.9% |
| Age 5 to 9 | 1.2% | 5.4% | 6.1% |
| Age 10 to 14 | 2.8% | 4.6% | 6.6% |
| Age 15 to 17 | 1.8% | 2.0% | 3.9% |
| Age 18 to 20 | 0.6% | 0.7% | 4.0% |
| Age 21 to 24 | 1.8% | 4.5% | 5.2% |
| Age 25 to 34 | 2.8% | 8.6% | 13.8% |
| Age 35 to 44 | 4.8% | 13.0% | 12.9% |
| Age 45 to 54 | 15.7% | 10.6% | 12.6% |
| Age 55 to 59 | 6.1% | 10.9% | 6.7% |
| Age 60 to 64 | 9.5% | 10.9% | 6.3% |
| Age 65 to 74 | 19.5% | 15.7% | 9.6% |
| Age 75 to 84 | 21.3% | 6.6% | 4.5% |
| Age 85 and over | 10.7% | 1.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Lely, FL | Big Pine Key, FL | United States |
| White | 82.3% | 79.4% | 59.4% |
| Black | 3.6% | 0.5% | 12.2% |
| Asian | 0.0% | 0.8% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.3% | 1.5% | 3.2% |
| Hispanic | 13.8% | 17.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Lely, FL | Big Pine Key, FL | United States |
| Married Population | 58.8% | 54.9% | 49.8% |
| Currently Married | 58.4% | 53.7% | 48.0% |
| Married but Separated | 0.5% | 1.2% | 1.8% |
| Single Population | 41.2% | 45.1% | 50.2% |
| Never Married | 15.6% | 22.7% | 33.8% |
| Divorced | 10.7% | 15.2% | 10.8% |
| Widowed | 14.8% | 7.2% | 5.6% |
| space5 | | | |
| Household Size | 1.88 | 2.50 | 2.60 |
| Households | 1,742 | 1,873 | 124,010,992 |
| Family Households | 1,055 | 1,193 | 80,755,759 |
| Married couple, w/children | 6.1% | 23.6% | 30.5% |
| Married couple, no children | 79.6% | 57.5% | 42.9% |
| Non Family Households | 687 | 680 | 43,255,233 |
| Single householder, w/children | 8.5% | 12.7% | 15.8% |
| Single householder, no children | 5.8% | 6.2% | 10.8% |