| | Phillipsburg, NJ | Trenton, NJ | United States |
| Population | 15,146 | 90,097 | 329,725,481 |
| Female Population | 51.0% | 50.9% | 50.5% |
| Male Population | 49.0% | 49.1% | 49.5% |
| Median Age | 40.3 | 36.1 | 38.4 |
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| Population - 2010 | 14,914 | 85,008 | 309,327,143 |
| Population - 2000 | 15,166 | 85,403 | 285,036,114 |
| Population - 1990 | 15,757 | 88,675 | 251,960,433 |
| Pop. 2000 to Now | -6.1% | -2.9% | 15.6% |
| Pop. 1990 to Now | -9.6% | -6.5% | 30.8% |
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| Population Density | 4,746.5 | 11,887.7 | 93.4 |
| Land Area | 3.2 | 7.6 | 3,531,905.4 |
| Water Area | 0.1 | 0.6 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Phillipsburg, NJ | Trenton, NJ | United States |
| Age 0 to 4 | 4.8% | 7.1% | 5.9% |
| Age 5 to 9 | 6.3% | 7.7% | 6.1% |
| Age 10 to 14 | 7.4% | 7.3% | 6.6% |
| Age 15 to 17 | 3.3% | 3.4% | 3.9% |
| Age 18 to 20 | 3.3% | 3.0% | 4.0% |
| Age 21 to 24 | 4.9% | 5.1% | 5.2% |
| Age 25 to 34 | 11.5% | 14.9% | 13.8% |
| Age 35 to 44 | 15.0% | 13.9% | 12.9% |
| Age 45 to 54 | 12.9% | 12.6% | 12.6% |
| Age 55 to 59 | 7.2% | 6.6% | 6.7% |
| Age 60 to 64 | 8.5% | 6.2% | 6.3% |
| Age 65 to 74 | 8.5% | 7.6% | 9.6% |
| Age 75 to 84 | 4.7% | 3.1% | 4.5% |
| Age 85 and over | 1.8% | 1.4% | 1.9% |
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| Race | | | |
| | Phillipsburg, NJ | Trenton, NJ | United States |
| White | 66.8% | 13.2% | 59.4% |
| Black | 9.8% | 47.2% | 12.2% |
| Asian | 1.7% | 0.9% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.4% | 0.2% | 0.4% |
| Two or More Races | 6.9% | 1.8% | 3.2% |
| Hispanic | 14.2% | 36.7% | 18.4% |
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| Marriage & Family | | | |
| | Phillipsburg, NJ | Trenton, NJ | United States |
| Married Population | 43.6% | 33.7% | 49.8% |
| Currently Married | 40.4% | 29.2% | 48.0% |
| Married but Separated | 3.2% | 4.5% | 1.8% |
| Single Population | 56.4% | 66.3% | 50.2% |
| Never Married | 35.0% | 49.9% | 33.8% |
| Divorced | 14.7% | 10.8% | 10.8% |
| Widowed | 6.8% | 5.6% | 5.6% |
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| Household Size | 2.32 | 2.75 | 2.60 |
| Households | 6,488 | 31,461 | 124,010,992 |
| Family Households | 3,626 | 17,730 | 80,755,759 |
| Married couple, w/children | 28.2% | 22.5% | 30.5% |
| Married couple, no children | 35.5% | 24.0% | 42.9% |
| Non Family Households | 2,862 | 13,731 | 43,255,233 |
| Single householder, w/children | 21.1% | 32.4% | 15.8% |
| Single householder, no children | 15.1% | 21.0% | 10.8% |