| | North Massapequa, NY | Lake Grove, NY | United States |
| Population | 18,577 | 11,110 | 329,725,481 |
| Female Population | 51.7% | 45.9% | 50.5% |
| Male Population | 48.3% | 54.1% | 49.5% |
| Median Age | 44.4 | 40.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 18,665 | 11,202 | 309,327,143 |
| Population - 2000 | 19,152 | 10,250 | 285,036,114 |
| Population - 1990 | 19,365 | 9,612 | 251,960,433 |
| Pop. 2000 to Now | -3.2% | 7.9% | 15.6% |
| Pop. 1990 to Now | -4.3% | 15.0% | 30.8% |
| space4 | | | |
| Population Density | 6,204.7 | 3,759.7 | 93.4 |
| Land Area | 3.0 | 3.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | North Massapequa, NY | Lake Grove, NY | United States |
| Age 0 to 4 | 6.3% | 4.5% | 5.9% |
| Age 5 to 9 | 5.2% | 8.0% | 6.1% |
| Age 10 to 14 | 3.2% | 8.4% | 6.6% |
| Age 15 to 17 | 3.7% | 3.3% | 3.9% |
| Age 18 to 20 | 3.7% | 2.8% | 4.0% |
| Age 21 to 24 | 5.1% | 5.9% | 5.2% |
| Age 25 to 34 | 14.3% | 11.1% | 13.8% |
| Age 35 to 44 | 9.1% | 11.2% | 12.9% |
| Age 45 to 54 | 12.5% | 15.1% | 12.6% |
| Age 55 to 59 | 9.4% | 9.4% | 6.7% |
| Age 60 to 64 | 8.1% | 5.3% | 6.3% |
| Age 65 to 74 | 10.0% | 6.9% | 9.6% |
| Age 75 to 84 | 6.6% | 5.7% | 4.5% |
| Age 85 and over | 2.8% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | North Massapequa, NY | Lake Grove, NY | United States |
| White | 90.6% | 72.4% | 59.4% |
| Black | 0.1% | 2.2% | 12.2% |
| Asian | 2.4% | 9.5% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.3% | 0.4% |
| Two or More Races | 0.8% | 1.4% | 3.2% |
| Hispanic | 6.2% | 14.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | North Massapequa, NY | Lake Grove, NY | United States |
| Married Population | 57.2% | 56.9% | 49.8% |
| Currently Married | 56.1% | 56.3% | 48.0% |
| Married but Separated | 1.1% | 0.6% | 1.8% |
| Single Population | 42.8% | 43.1% | 50.2% |
| Never Married | 30.6% | 29.4% | 33.8% |
| Divorced | 6.2% | 7.9% | 10.8% |
| Widowed | 6.0% | 5.9% | 5.6% |
| space5 | | | |
| Household Size | 2.91 | 3.01 | 2.60 |
| Households | 6,385 | 3,686 | 124,010,992 |
| Family Households | 4,952 | 2,843 | 80,755,759 |
| Married couple, w/children | 34.0% | 35.4% | 30.5% |
| Married couple, no children | 51.2% | 44.7% | 42.9% |
| Non Family Households | 1,433 | 843 | 43,255,233 |
| Single householder, w/children | 4.7% | 6.8% | 15.8% |
| Single householder, no children | 10.1% | 13.2% | 10.8% |