| | Port Chester, NY | Thornwood, NY | United States |
| Population | 31,317 | 4,375 | 329,725,481 |
| Female Population | 46.8% | 51.0% | 50.5% |
| Male Population | 53.2% | 49.0% | 49.5% |
| Median Age | 38.2 | 38.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 28,955 | 3,672 | 309,327,143 |
| Population - 2000 | 27,867 | 5,980 | 285,036,114 |
| Population - 1990 | 24,728 | 7,025 | 251,960,433 |
| Pop. 2000 to Now | 3.6% | -34.1% | 15.6% |
| Pop. 1990 to Now | 16.7% | -43.9% | 30.8% |
| space4 | | | |
| Population Density | 13,435.0 | 3,962.9 | 93.4 |
| Land Area | 2.3 | 1.1 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Port Chester, NY | Thornwood, NY | United States |
| Age 0 to 4 | 6.4% | 7.1% | 5.9% |
| Age 5 to 9 | 5.7% | 8.1% | 6.1% |
| Age 10 to 14 | 5.4% | 4.9% | 6.6% |
| Age 15 to 17 | 3.5% | 4.0% | 3.9% |
| Age 18 to 20 | 4.3% | 2.5% | 4.0% |
| Age 21 to 24 | 5.7% | 5.4% | 5.2% |
| Age 25 to 34 | 14.4% | 9.5% | 13.8% |
| Age 35 to 44 | 16.6% | 12.9% | 12.9% |
| Age 45 to 54 | 13.2% | 16.7% | 12.6% |
| Age 55 to 59 | 5.3% | 6.0% | 6.7% |
| Age 60 to 64 | 7.2% | 7.6% | 6.3% |
| Age 65 to 74 | 6.8% | 7.1% | 9.6% |
| Age 75 to 84 | 3.3% | 3.8% | 4.5% |
| Age 85 and over | 2.2% | 4.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Port Chester, NY | Thornwood, NY | United States |
| White | 27.7% | 80.2% | 59.4% |
| Black | 5.2% | 2.0% | 12.2% |
| Asian | 1.4% | 4.5% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.7% | 0.2% | 0.4% |
| Two or More Races | 0.7% | 2.5% | 3.2% |
| Hispanic | 64.2% | 10.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Port Chester, NY | Thornwood, NY | United States |
| Married Population | 51.5% | 61.6% | 49.8% |
| Currently Married | 48.9% | 60.6% | 48.0% |
| Married but Separated | 2.6% | 1.0% | 1.8% |
| Single Population | 48.5% | 38.4% | 50.2% |
| Never Married | 35.2% | 27.7% | 33.8% |
| Divorced | 9.2% | 6.0% | 10.8% |
| Widowed | 4.2% | 4.7% | 5.6% |
| space5 | | | |
| Household Size | 3.16 | 3.11 | 2.60 |
| Households | 9,829 | 1,389 | 124,010,992 |
| Family Households | 7,238 | 1,096 | 80,755,759 |
| Married couple, w/children | 30.8% | 45.1% | 30.5% |
| Married couple, no children | 41.8% | 44.4% | 42.9% |
| Non Family Households | 2,591 | 293 | 43,255,233 |
| Single householder, w/children | 18.1% | 5.1% | 15.8% |
| Single householder, no children | 9.3% | 5.4% | 10.8% |