| | Moriches, NY | Shirley, NY | United States |
| Population | 2,685 | 28,059 | 329,725,481 |
| Female Population | 54.0% | 48.2% | 50.5% |
| Male Population | 46.0% | 51.8% | 49.5% |
| Median Age | 56.3 | 39 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,016 | 28,070 | 309,327,143 |
| Population - 2000 | 2,319 | 25,395 | 285,036,114 |
| Population - 1990 | 2,085 | 22,936 | 251,960,433 |
| Pop. 2000 to Now | 31.7% | 5.8% | 15.6% |
| Pop. 1990 to Now | 46.5% | 17.1% | 30.8% |
| space4 | | | |
| Population Density | 1,293.4 | 2,445.9 | 93.4 |
| Land Area | 2.1 | 11.5 | 3,531,905.4 |
| Water Area | 0.2 | 0.4 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Moriches, NY | Shirley, NY | United States |
| Age 0 to 4 | 9.4% | 5.6% | 5.9% |
| Age 5 to 9 | 2.3% | 7.0% | 6.1% |
| Age 10 to 14 | 1.5% | 6.5% | 6.6% |
| Age 15 to 17 | 1.6% | 3.3% | 3.9% |
| Age 18 to 20 | 0.4% | 4.4% | 4.0% |
| Age 21 to 24 | 4.4% | 5.5% | 5.2% |
| Age 25 to 34 | 13.3% | 12.1% | 13.8% |
| Age 35 to 44 | 6.8% | 14.0% | 12.9% |
| Age 45 to 54 | 9.4% | 11.6% | 12.6% |
| Age 55 to 59 | 6.7% | 10.9% | 6.7% |
| Age 60 to 64 | 7.9% | 5.9% | 6.3% |
| Age 65 to 74 | 20.4% | 9.7% | 9.6% |
| Age 75 to 84 | 10.9% | 1.9% | 4.5% |
| Age 85 and over | 5.1% | 1.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Moriches, NY | Shirley, NY | United States |
| White | 86.3% | 65.6% | 59.4% |
| Black | 2.4% | 7.3% | 12.2% |
| Asian | 1.4% | 3.4% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 3.8% | 2.4% | 3.2% |
| Hispanic | 6.1% | 21.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Moriches, NY | Shirley, NY | United States |
| Married Population | 59.3% | 47.6% | 49.8% |
| Currently Married | 57.2% | 46.0% | 48.0% |
| Married but Separated | 2.1% | 1.6% | 1.8% |
| Single Population | 40.7% | 52.4% | 50.2% |
| Never Married | 24.7% | 36.7% | 33.8% |
| Divorced | 8.1% | 9.8% | 10.8% |
| Widowed | 7.9% | 5.9% | 5.6% |
| space5 | | | |
| Household Size | 2.02 | 3.40 | 2.60 |
| Households | 1,326 | 8,168 | 124,010,992 |
| Family Households | 787 | 6,403 | 80,755,759 |
| Married couple, w/children | 19.3% | 32.7% | 30.5% |
| Married couple, no children | 56.5% | 39.2% | 42.9% |
| Non Family Households | 539 | 1,765 | 43,255,233 |
| Single householder, w/children | 9.3% | 14.6% | 15.8% |
| Single householder, no children | 14.9% | 13.5% | 10.8% |