| | Heathrow, FL | Mechanicsburg, PA | United States |
| Population | 6,981 | 9,310 | 329,725,481 |
| Female Population | 51.9% | 48.5% | 50.5% |
| Male Population | 48.2% | 51.5% | 49.5% |
| Median Age | 45.8 | 38.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 5,912 | 8,937 | 309,327,143 |
| Population - 2000 | 4,068 | 9,042 | 285,036,114 |
| Population - 1990 | 977 | 9,452 | 251,960,433 |
| Pop. 2000 to Now | 59.4% | -0.3% | 15.6% |
| Pop. 1990 to Now | 563.9% | -4.6% | 30.8% |
| space4 | | | |
| Population Density | 2,545.0 | 3,863.1 | 93.4 |
| Land Area | 2.7 | 2.4 | 3,531,905.4 |
| Water Area | 0.4 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Heathrow, FL | Mechanicsburg, PA | United States |
| Age 0 to 4 | 3.5% | 4.3% | 5.9% |
| Age 5 to 9 | 6.8% | 7.4% | 6.1% |
| Age 10 to 14 | 5.7% | 6.9% | 6.6% |
| Age 15 to 17 | 3.4% | 1.8% | 3.9% |
| Age 18 to 20 | 1.9% | 1.4% | 4.0% |
| Age 21 to 24 | 5.0% | 5.1% | 5.2% |
| Age 25 to 34 | 8.3% | 17.6% | 13.8% |
| Age 35 to 44 | 14.7% | 13.9% | 12.9% |
| Age 45 to 54 | 12.7% | 10.4% | 12.6% |
| Age 55 to 59 | 10.9% | 9.8% | 6.7% |
| Age 60 to 64 | 7.1% | 5.0% | 6.3% |
| Age 65 to 74 | 11.8% | 8.6% | 9.6% |
| Age 75 to 84 | 6.2% | 6.0% | 4.5% |
| Age 85 and over | 1.9% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Heathrow, FL | Mechanicsburg, PA | United States |
| White | 68.0% | 84.7% | 59.4% |
| Black | 5.0% | 2.1% | 12.2% |
| Asian | 14.7% | 1.6% | 5.6% |
| Native American | 0.4% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.1% | 4.4% | 3.2% |
| Hispanic | 10.9% | 7.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Heathrow, FL | Mechanicsburg, PA | United States |
| Married Population | 67.0% | 50.1% | 49.8% |
| Currently Married | 67.0% | 47.3% | 48.0% |
| Married but Separated | 0.0% | 2.8% | 1.8% |
| Single Population | 33.0% | 49.9% | 50.2% |
| Never Married | 20.5% | 31.2% | 33.8% |
| Divorced | 5.2% | 12.2% | 10.8% |
| Widowed | 7.3% | 6.5% | 5.6% |
| space5 | | | |
| Household Size | 2.30 | 2.29 | 2.60 |
| Households | 3,029 | 4,037 | 124,010,992 |
| Family Households | 2,145 | 2,496 | 80,755,759 |
| Married couple, w/children | 27.9% | 25.3% | 30.5% |
| Married couple, no children | 58.4% | 45.7% | 42.9% |
| Non Family Households | 884 | 1,541 | 43,255,233 |
| Single householder, w/children | 7.8% | 15.4% | 15.8% |
| Single householder, no children | 5.8% | 13.6% | 10.8% |