| | North Bay Shore, NY | Central Islip, NY | United States |
| Population | 18,524 | 36,292 | 329,725,481 |
| Female Population | 49.9% | 48.8% | 50.5% |
| Male Population | 50.1% | 51.3% | 49.5% |
| Median Age | 34.7 | 34.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 19,515 | 35,912 | 309,327,143 |
| Population - 2000 | 14,992 | 31,950 | 285,036,114 |
| Population - 1990 | 12,799 | 26,028 | 251,960,433 |
| Pop. 2000 to Now | 44.3% | 2.8% | 15.6% |
| Pop. 1990 to Now | 69.0% | 26.2% | 30.8% |
| space4 | | | |
| Population Density | 5,763.5 | 5,105.1 | 93.4 |
| Land Area | 3.2 | 7.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | North Bay Shore, NY | Central Islip, NY | United States |
| Age 0 to 4 | 6.3% | 7.0% | 5.9% |
| Age 5 to 9 | 7.0% | 4.7% | 6.1% |
| Age 10 to 14 | 7.8% | 7.7% | 6.6% |
| Age 15 to 17 | 2.7% | 4.9% | 3.9% |
| Age 18 to 20 | 5.4% | 6.1% | 4.0% |
| Age 21 to 24 | 6.4% | 5.4% | 5.2% |
| Age 25 to 34 | 14.8% | 14.7% | 13.8% |
| Age 35 to 44 | 13.6% | 14.9% | 12.9% |
| Age 45 to 54 | 14.4% | 14.0% | 12.6% |
| Age 55 to 59 | 5.2% | 5.9% | 6.7% |
| Age 60 to 64 | 4.8% | 5.0% | 6.3% |
| Age 65 to 74 | 6.9% | 5.8% | 9.6% |
| Age 75 to 84 | 3.7% | 3.4% | 4.5% |
| Age 85 and over | 1.1% | 0.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | North Bay Shore, NY | Central Islip, NY | United States |
| White | 16.2% | 17.3% | 59.4% |
| Black | 11.2% | 20.9% | 12.2% |
| Asian | 4.3% | 2.0% | 5.6% |
| Native American | 0.2% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.7% | 0.7% | 0.4% |
| Two or More Races | 1.6% | 1.4% | 3.2% |
| Hispanic | 64.9% | 57.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | North Bay Shore, NY | Central Islip, NY | United States |
| Married Population | 46.0% | 36.9% | 49.8% |
| Currently Married | 43.3% | 34.3% | 48.0% |
| Married but Separated | 2.8% | 2.6% | 1.8% |
| Single Population | 54.0% | 63.1% | 50.2% |
| Never Married | 39.7% | 47.7% | 33.8% |
| Divorced | 9.9% | 12.3% | 10.8% |
| Widowed | 4.4% | 3.2% | 5.6% |
| space5 | | | |
| Household Size | 4.19 | 3.87 | 2.60 |
| Households | 4,416 | 9,331 | 124,010,992 |
| Family Households | 3,580 | 6,638 | 80,755,759 |
| Married couple, w/children | 44.7% | 29.4% | 30.5% |
| Married couple, no children | 26.1% | 26.4% | 42.9% |
| Non Family Households | 836 | 2,693 | 43,255,233 |
| Single householder, w/children | 15.1% | 22.2% | 15.8% |
| Single householder, no children | 14.1% | 22.0% | 10.8% |