| | Youngsville, NC | St. Augustine South, FL | United States |
| Population | 2,503 | 5,354 | 329,725,481 |
| Female Population | 47.6% | 50.5% | 50.5% |
| Male Population | 52.4% | 49.5% | 49.5% |
| Median Age | 29.7 | 50.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,153 | 5,350 | 309,327,143 |
| Population - 2000 | 651 | 5,035 | 285,036,114 |
| Population - 1990 | 424 | 4,218 | 251,960,433 |
| Pop. 2000 to Now | 117.1% | 28.8% | 15.6% |
| Pop. 1990 to Now | 233.3% | 53.7% | 30.8% |
| space4 | | | |
| Population Density | 1,441.0 | 3,377.9 | 93.4 |
| Land Area | 1.7 | 1.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Youngsville, NC | St. Augustine South, FL | United States |
| Age 0 to 4 | 3.8% | 5.4% | 5.9% |
| Age 5 to 9 | 10.7% | 2.7% | 6.1% |
| Age 10 to 14 | 10.7% | 4.2% | 6.6% |
| Age 15 to 17 | 4.3% | 3.3% | 3.9% |
| Age 18 to 20 | 3.2% | 3.4% | 4.0% |
| Age 21 to 24 | 7.2% | 4.2% | 5.2% |
| Age 25 to 34 | 17.5% | 14.3% | 13.8% |
| Age 35 to 44 | 16.5% | 9.8% | 12.9% |
| Age 45 to 54 | 10.5% | 11.9% | 12.6% |
| Age 55 to 59 | 6.4% | 10.0% | 6.7% |
| Age 60 to 64 | 2.2% | 9.1% | 6.3% |
| Age 65 to 74 | 4.3% | 10.3% | 9.6% |
| Age 75 to 84 | 2.3% | 8.6% | 4.5% |
| Age 85 and over | 0.2% | 2.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Youngsville, NC | St. Augustine South, FL | United States |
| White | 53.5% | 87.2% | 59.4% |
| Black | 32.6% | 0.5% | 12.2% |
| Asian | 0.9% | 4.8% | 5.6% |
| Native American | 0.6% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.9% | 3.5% | 3.2% |
| Hispanic | 9.5% | 4.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Youngsville, NC | St. Augustine South, FL | United States |
| Married Population | 46.0% | 48.3% | 49.8% |
| Currently Married | 41.5% | 47.5% | 48.0% |
| Married but Separated | 4.5% | 0.7% | 1.8% |
| Single Population | 54.0% | 51.7% | 50.2% |
| Never Married | 40.4% | 27.9% | 33.8% |
| Divorced | 8.8% | 18.3% | 10.8% |
| Widowed | 4.9% | 5.5% | 5.6% |
| space5 | | | |
| Household Size | 2.53 | 2.56 | 2.60 |
| Households | 991 | 2,082 | 124,010,992 |
| Family Households | 683 | 1,388 | 80,755,759 |
| Married couple, w/children | 32.7% | 26.4% | 30.5% |
| Married couple, no children | 24.9% | 49.9% | 42.9% |
| Non Family Households | 308 | 694 | 43,255,233 |
| Single householder, w/children | 33.7% | 10.7% | 15.8% |
| Single householder, no children | 8.8% | 13.0% | 10.8% |