| | Hemlock Farms, PA | West Hempstead, NY | United States |
| Population | 3,385 | 20,729 | 329,725,481 |
| Female Population | 49.9% | 50.3% | 50.5% |
| Male Population | 50.1% | 49.7% | 49.5% |
| Median Age | 55.9 | 38.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,912 | 18,435 | 309,327,143 |
| Population - 2000 | 2,465 | 18,713 | 285,036,114 |
| Population - 1990 | 1,255 | 17,689 | 251,960,433 |
| Pop. 2000 to Now | 37.7% | 5.7% | 15.6% |
| Pop. 1990 to Now | 170.4% | 11.9% | 30.8% |
| space4 | | | |
| Population Density | 439.3 | 7,804.6 | 93.4 |
| Land Area | 7.7 | 2.7 | 3,531,905.4 |
| Water Area | 0.4 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Hemlock Farms, PA | West Hempstead, NY | United States |
| Age 0 to 4 | 1.6% | 6.2% | 5.9% |
| Age 5 to 9 | 6.6% | 6.5% | 6.1% |
| Age 10 to 14 | 5.0% | 6.4% | 6.6% |
| Age 15 to 17 | 1.2% | 4.1% | 3.9% |
| Age 18 to 20 | 2.6% | 3.3% | 4.0% |
| Age 21 to 24 | 0.0% | 6.0% | 5.2% |
| Age 25 to 34 | 4.7% | 14.3% | 13.8% |
| Age 35 to 44 | 6.9% | 10.8% | 12.9% |
| Age 45 to 54 | 17.9% | 14.0% | 12.6% |
| Age 55 to 59 | 14.7% | 7.2% | 6.7% |
| Age 60 to 64 | 5.5% | 6.9% | 6.3% |
| Age 65 to 74 | 19.9% | 8.4% | 9.6% |
| Age 75 to 84 | 9.0% | 3.8% | 4.5% |
| Age 85 and over | 4.4% | 2.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Hemlock Farms, PA | West Hempstead, NY | United States |
| White | 75.8% | 56.7% | 59.4% |
| Black | 2.3% | 10.3% | 12.2% |
| Asian | 1.6% | 4.6% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.5% | 0.4% |
| Two or More Races | 8.6% | 1.7% | 3.2% |
| Hispanic | 11.6% | 26.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Hemlock Farms, PA | West Hempstead, NY | United States |
| Married Population | 55.9% | 50.0% | 49.8% |
| Currently Married | 55.7% | 48.2% | 48.0% |
| Married but Separated | 0.2% | 1.7% | 1.8% |
| Single Population | 44.1% | 50.0% | 50.2% |
| Never Married | 22.8% | 37.5% | 33.8% |
| Divorced | 13.7% | 6.8% | 10.8% |
| Widowed | 7.6% | 5.6% | 5.6% |
| space5 | | | |
| Household Size | 2.20 | 3.47 | 2.60 |
| Households | 1,542 | 5,961 | 124,010,992 |
| Family Households | 969 | 4,887 | 80,755,759 |
| Married couple, w/children | 28.2% | 35.0% | 30.5% |
| Married couple, no children | 54.3% | 39.9% | 42.9% |
| Non Family Households | 573 | 1,074 | 43,255,233 |
| Single householder, w/children | 4.1% | 12.6% | 15.8% |
| Single householder, no children | 13.4% | 12.6% | 10.8% |