| | Gap, PA | Marina, CA | United States |
| Population | 2,381 | 22,246 | 329,725,481 |
| Female Population | 49.8% | 51.4% | 50.5% |
| Male Population | 50.2% | 48.6% | 49.5% |
| Median Age | 34.6 | 34.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,246 | 19,731 | 309,327,143 |
| Population - 2000 | 1,611 | 25,101 | 285,036,114 |
| Population - 1990 | 1,226 | 26,436 | 251,960,433 |
| Pop. 2000 to Now | 32.8% | -13.0% | 15.6% |
| Pop. 1990 to Now | 74.5% | -17.4% | 30.8% |
| space4 | | | |
| Population Density | 846.7 | 2,502.6 | 93.4 |
| Land Area | 2.8 | 8.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.9 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Gap, PA | Marina, CA | United States |
| Age 0 to 4 | 6.2% | 6.3% | 5.9% |
| Age 5 to 9 | 8.7% | 5.9% | 6.1% |
| Age 10 to 14 | 5.7% | 5.2% | 6.6% |
| Age 15 to 17 | 7.1% | 3.3% | 3.9% |
| Age 18 to 20 | 2.6% | 6.1% | 4.0% |
| Age 21 to 24 | 4.0% | 8.4% | 5.2% |
| Age 25 to 34 | 16.0% | 15.1% | 13.8% |
| Age 35 to 44 | 15.1% | 11.6% | 12.9% |
| Age 45 to 54 | 12.3% | 10.6% | 12.6% |
| Age 55 to 59 | 8.2% | 6.4% | 6.7% |
| Age 60 to 64 | 1.6% | 6.6% | 6.3% |
| Age 65 to 74 | 6.1% | 8.4% | 9.6% |
| Age 75 to 84 | 5.4% | 4.9% | 4.5% |
| Age 85 and over | 1.0% | 1.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Gap, PA | Marina, CA | United States |
| White | 83.1% | 38.4% | 59.4% |
| Black | 7.9% | 6.6% | 12.2% |
| Asian | 0.5% | 15.5% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 2.0% | 0.2% |
| Other | 0.0% | 0.5% | 0.4% |
| Two or More Races | 4.3% | 8.7% | 3.2% |
| Hispanic | 4.2% | 28.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Gap, PA | Marina, CA | United States |
| Married Population | 57.8% | 46.0% | 49.8% |
| Currently Married | 56.7% | 44.2% | 48.0% |
| Married but Separated | 1.1% | 1.8% | 1.8% |
| Single Population | 42.2% | 54.0% | 50.2% |
| Never Married | 30.5% | 39.8% | 33.8% |
| Divorced | 8.3% | 9.5% | 10.8% |
| Widowed | 3.4% | 4.6% | 5.6% |
| space5 | | | |
| Household Size | 3.08 | 2.72 | 2.60 |
| Households | 773 | 7,676 | 124,010,992 |
| Family Households | 613 | 4,925 | 80,755,759 |
| Married couple, w/children | 35.7% | 31.1% | 30.5% |
| Married couple, no children | 44.5% | 41.0% | 42.9% |
| Non Family Households | 160 | 2,751 | 43,255,233 |
| Single householder, w/children | 9.0% | 14.4% | 15.8% |
| Single householder, no children | 10.8% | 13.5% | 10.8% |