| | Milroy, PA | Gap, PA | United States |
| Population | 1,522 | 2,381 | 329,725,481 |
| Female Population | 56.2% | 49.8% | 50.5% |
| Male Population | 43.8% | 50.2% | 49.5% |
| Median Age | 49.3 | 34.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,287 | 1,246 | 309,327,143 |
| Population - 2000 | 1,386 | 1,611 | 285,036,114 |
| Population - 1990 | 1,456 | 1,226 | 251,960,433 |
| Pop. 2000 to Now | 22.1% | 32.8% | 15.6% |
| Pop. 1990 to Now | 16.2% | 74.5% | 30.8% |
| space4 | | | |
| Population Density | 1,508.4 | 846.7 | 93.4 |
| Land Area | 1.0 | 2.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Milroy, PA | Gap, PA | United States |
| Age 0 to 4 | 4.5% | 6.2% | 5.9% |
| Age 5 to 9 | 5.3% | 8.7% | 6.1% |
| Age 10 to 14 | 3.1% | 5.7% | 6.6% |
| Age 15 to 17 | 3.9% | 7.1% | 3.9% |
| Age 18 to 20 | 7.2% | 2.6% | 4.0% |
| Age 21 to 24 | 2.8% | 4.0% | 5.2% |
| Age 25 to 34 | 9.7% | 16.0% | 13.8% |
| Age 35 to 44 | 9.4% | 15.1% | 12.9% |
| Age 45 to 54 | 21.9% | 12.3% | 12.6% |
| Age 55 to 59 | 4.9% | 8.2% | 6.7% |
| Age 60 to 64 | 3.8% | 1.6% | 6.3% |
| Age 65 to 74 | 14.0% | 6.1% | 9.6% |
| Age 75 to 84 | 7.5% | 5.4% | 4.5% |
| Age 85 and over | 2.0% | 1.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Milroy, PA | Gap, PA | United States |
| White | 89.8% | 83.1% | 59.4% |
| Black | 0.0% | 7.9% | 12.2% |
| Asian | 0.0% | 0.5% | 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 | 1.8% | 4.3% | 3.2% |
| Hispanic | 8.4% | 4.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Milroy, PA | Gap, PA | United States |
| Married Population | 52.2% | 57.8% | 49.8% |
| Currently Married | 49.2% | 56.7% | 48.0% |
| Married but Separated | 2.9% | 1.1% | 1.8% |
| Single Population | 47.8% | 42.2% | 50.2% |
| Never Married | 29.9% | 30.5% | 33.8% |
| Divorced | 9.7% | 8.3% | 10.8% |
| Widowed | 8.3% | 3.4% | 5.6% |
| space5 | | | |
| Household Size | 2.14 | 3.08 | 2.60 |
| Households | 712 | 773 | 124,010,992 |
| Family Households | 479 | 613 | 80,755,759 |
| Married couple, w/children | 14.8% | 35.7% | 30.5% |
| Married couple, no children | 54.5% | 44.5% | 42.9% |
| Non Family Households | 233 | 160 | 43,255,233 |
| Single householder, w/children | 21.7% | 9.0% | 15.8% |
| Single householder, no children | 9.0% | 10.8% | 10.8% |