| | Middle Island, NY | Towson, MD | United States |
| Population | 11,129 | 59,014 | 329,725,481 |
| Female Population | 55.2% | 52.7% | 50.5% |
| Male Population | 44.8% | 47.3% | 49.5% |
| Median Age | 44.4 | 33 | 38.4 |
| space3 | | | |
| Population - 2010 | 10,230 | 54,068 | 309,327,143 |
| Population - 2000 | 9,702 | 51,793 | 285,036,114 |
| Population - 1990 | 7,848 | 49,445 | 251,960,433 |
| Pop. 2000 to Now | 6.0% | 13.2% | 15.6% |
| Pop. 1990 to Now | 31.0% | 18.6% | 30.8% |
| space4 | | | |
| Population Density | 1,354.1 | 4,169.7 | 93.4 |
| Land Area | 8.2 | 14.2 | 3,531,905.4 |
| Water Area | 0.1 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Middle Island, NY | Towson, MD | United States |
| Age 0 to 4 | 6.0% | 4.5% | 5.9% |
| Age 5 to 9 | 4.9% | 5.1% | 6.1% |
| Age 10 to 14 | 5.1% | 5.3% | 6.6% |
| Age 15 to 17 | 3.1% | 2.9% | 3.9% |
| Age 18 to 20 | 2.6% | 11.2% | 4.0% |
| Age 21 to 24 | 4.3% | 9.6% | 5.2% |
| Age 25 to 34 | 11.3% | 13.9% | 13.8% |
| Age 35 to 44 | 13.4% | 9.8% | 12.9% |
| Age 45 to 54 | 12.8% | 9.6% | 12.6% |
| Age 55 to 59 | 7.4% | 4.6% | 6.7% |
| Age 60 to 64 | 7.8% | 5.4% | 6.3% |
| Age 65 to 74 | 12.6% | 9.6% | 9.6% |
| Age 75 to 84 | 5.3% | 4.9% | 4.5% |
| Age 85 and over | 3.4% | 3.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Middle Island, NY | Towson, MD | United States |
| White | 74.9% | 70.4% | 59.4% |
| Black | 6.9% | 15.6% | 12.2% |
| Asian | 2.0% | 5.8% | 5.6% |
| Native American | 0.1% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.3% | 0.4% | 0.4% |
| Two or More Races | 1.4% | 3.5% | 3.2% |
| Hispanic | 14.4% | 4.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Middle Island, NY | Towson, MD | United States |
| Married Population | 43.3% | 41.7% | 49.8% |
| Currently Married | 40.8% | 39.9% | 48.0% |
| Married but Separated | 2.5% | 1.8% | 1.8% |
| Single Population | 56.7% | 58.3% | 50.2% |
| Never Married | 32.7% | 43.2% | 33.8% |
| Divorced | 16.9% | 8.8% | 10.8% |
| Widowed | 7.1% | 6.4% | 5.6% |
| space5 | | | |
| Household Size | 2.41 | 2.30 | 2.60 |
| Households | 4,513 | 22,191 | 124,010,992 |
| Family Households | 2,618 | 12,111 | 80,755,759 |
| Married couple, w/children | 24.2% | 34.5% | 30.5% |
| Married couple, no children | 42.1% | 43.2% | 42.9% |
| Non Family Households | 1,895 | 10,080 | 43,255,233 |
| Single householder, w/children | 15.6% | 12.7% | 15.8% |
| Single householder, no children | 18.1% | 9.6% | 10.8% |