| | Iselin, NJ | Princeton, WV | United States |
| Population | 17,684 | 5,885 | 329,725,481 |
| Female Population | 51.3% | 49.0% | 50.5% |
| Male Population | 48.7% | 51.0% | 49.5% |
| Median Age | 42.8 | 43.6 | 38.4 |
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| Population - 2010 | 18,726 | 6,108 | 309,327,143 |
| Population - 2000 | 16,698 | 6,347 | 285,036,114 |
| Population - 1990 | 16,141 | 7,043 | 251,960,433 |
| Pop. 2000 to Now | 15.9% | -11.8% | 15.6% |
| Pop. 1990 to Now | 19.9% | -20.5% | 30.8% |
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| Population Density | 5,547.1 | 1,952.6 | 93.4 |
| Land Area | 3.2 | 3.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Iselin, NJ | Princeton, WV | United States |
| Age 0 to 4 | 3.6% | 5.4% | 5.9% |
| Age 5 to 9 | 6.9% | 8.2% | 6.1% |
| Age 10 to 14 | 6.6% | 3.4% | 6.6% |
| Age 15 to 17 | 1.8% | 3.3% | 3.9% |
| Age 18 to 20 | 2.9% | 3.2% | 4.0% |
| Age 21 to 24 | 3.6% | 4.4% | 5.2% |
| Age 25 to 34 | 12.5% | 14.4% | 13.8% |
| Age 35 to 44 | 14.9% | 10.1% | 12.9% |
| Age 45 to 54 | 13.2% | 14.3% | 12.6% |
| Age 55 to 59 | 7.8% | 4.5% | 6.7% |
| Age 60 to 64 | 6.7% | 5.4% | 6.3% |
| Age 65 to 74 | 12.6% | 13.1% | 9.6% |
| Age 75 to 84 | 5.6% | 5.2% | 4.5% |
| Age 85 and over | 1.4% | 5.1% | 1.9% |
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| Race | | | |
| | Iselin, NJ | Princeton, WV | United States |
| White | 27.8% | 88.8% | 59.4% |
| Black | 7.4% | 6.1% | 12.2% |
| Asian | 52.3% | 0.4% | 5.6% |
| Native American | 0.8% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.0% | 0.4% |
| Two or More Races | 3.7% | 4.0% | 3.2% |
| Hispanic | 7.8% | 0.6% | 18.4% |
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| Marriage & Family | | | |
| | Iselin, NJ | Princeton, WV | United States |
| Married Population | 63.5% | 44.8% | 49.8% |
| Currently Married | 62.8% | 42.2% | 48.0% |
| Married but Separated | 0.7% | 2.6% | 1.8% |
| Single Population | 36.5% | 55.2% | 50.2% |
| Never Married | 24.4% | 29.9% | 33.8% |
| Divorced | 4.5% | 15.5% | 10.8% |
| Widowed | 7.6% | 9.7% | 5.6% |
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| Household Size | 2.76 | 2.26 | 2.60 |
| Households | 6,410 | 2,600 | 124,010,992 |
| Family Households | 5,007 | 1,586 | 80,755,759 |
| Married couple, w/children | 32.8% | 21.9% | 30.5% |
| Married couple, no children | 46.7% | 41.5% | 42.9% |
| Non Family Households | 1,403 | 1,014 | 43,255,233 |
| Single householder, w/children | 9.9% | 26.7% | 15.8% |
| Single householder, no children | 10.6% | 9.8% | 10.8% |