| | Fort Pierce South, FL | Cedar Key, FL | United States |
| Population | 4,615 | 897 | 329,725,481 |
| Female Population | 54.4% | 51.1% | 50.5% |
| Male Population | 45.6% | 48.9% | 49.5% |
| Median Age | 40.3 | 54.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 5,692 | 729 | 309,327,143 |
| Population - 2000 | 5,672 | 790 | 285,036,114 |
| Population - 1990 | 5,320 | 668 | 251,960,433 |
| Pop. 2000 to Now | -13.7% | -8.1% | 15.6% |
| Pop. 1990 to Now | -8.0% | 8.7% | 30.8% |
| space4 | | | |
| Population Density | 1,703.0 | 925.7 | 93.4 |
| Land Area | 2.7 | 1.0 | 3,531,905.4 |
| Water Area | 0.0 | 1.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Fort Pierce South, FL | Cedar Key, FL | United States |
| Age 0 to 4 | 2.1% | 5.5% | 5.9% |
| Age 5 to 9 | 3.7% | 0.0% | 6.1% |
| Age 10 to 14 | 8.0% | 3.3% | 6.6% |
| Age 15 to 17 | 5.5% | 1.0% | 3.9% |
| Age 18 to 20 | 2.1% | 8.4% | 4.0% |
| Age 21 to 24 | 2.8% | 9.4% | 5.2% |
| Age 25 to 34 | 18.4% | 8.7% | 13.8% |
| Age 35 to 44 | 10.3% | 3.9% | 12.9% |
| Age 45 to 54 | 16.5% | 11.1% | 12.6% |
| Age 55 to 59 | 5.7% | 3.9% | 6.7% |
| Age 60 to 64 | 2.9% | 6.5% | 6.3% |
| Age 65 to 74 | 14.3% | 21.0% | 9.6% |
| Age 75 to 84 | 3.9% | 15.9% | 4.5% |
| Age 85 and over | 3.7% | 1.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Fort Pierce South, FL | Cedar Key, FL | United States |
| White | 59.1% | 87.3% | 59.4% |
| Black | 8.0% | 10.1% | 12.2% |
| Asian | 0.0% | 0.0% | 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 | 1.5% | 2.6% | 3.2% |
| Hispanic | 31.4% | 0.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Fort Pierce South, FL | Cedar Key, FL | United States |
| Married Population | 46.3% | 53.9% | 49.8% |
| Currently Married | 44.3% | 53.5% | 48.0% |
| Married but Separated | 2.0% | 0.4% | 1.8% |
| Single Population | 53.7% | 46.1% | 50.2% |
| Never Married | 29.7% | 28.0% | 33.8% |
| Divorced | 15.4% | 12.6% | 10.8% |
| Widowed | 8.7% | 5.5% | 5.6% |
| space5 | | | |
| Household Size | 2.51 | 2.25 | 2.60 |
| Households | 1,836 | 391 | 124,010,992 |
| Family Households | 1,051 | 275 | 80,755,759 |
| Married couple, w/children | 26.5% | 10.5% | 30.5% |
| Married couple, no children | 43.4% | 55.3% | 42.9% |
| Non Family Households | 785 | 116 | 43,255,233 |
| Single householder, w/children | 22.3% | 22.2% | 15.8% |
| Single householder, no children | 7.8% | 12.0% | 10.8% |