| | Plainfield, NJ | Passaic, NJ | United States |
| Population | 54,183 | 70,308 | 329,725,481 |
| Female Population | 47.6% | 51.2% | 50.5% |
| Male Population | 52.4% | 48.9% | 49.5% |
| Median Age | 34.1 | 30 | 38.4 |
| space3 | | | |
| Population - 2010 | 49,622 | 69,800 | 309,327,143 |
| Population - 2000 | 47,829 | 67,861 | 285,036,114 |
| Population - 1990 | 46,567 | 58,041 | 251,960,433 |
| Pop. 2000 to Now | 4.6% | 2.2% | 15.6% |
| Pop. 1990 to Now | 7.4% | 19.5% | 30.8% |
| space4 | | | |
| Population Density | 9,092.6 | 22,441.1 | 93.4 |
| Land Area | 6.0 | 3.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Plainfield, NJ | Passaic, NJ | United States |
| Age 0 to 4 | 7.2% | 8.8% | 5.9% |
| Age 5 to 9 | 7.9% | 9.0% | 6.1% |
| Age 10 to 14 | 7.5% | 9.4% | 6.6% |
| Age 15 to 17 | 4.4% | 5.1% | 3.9% |
| Age 18 to 20 | 3.5% | 5.7% | 4.0% |
| Age 21 to 24 | 5.4% | 5.7% | 5.2% |
| Age 25 to 34 | 15.5% | 13.7% | 13.8% |
| Age 35 to 44 | 13.9% | 13.9% | 12.9% |
| Age 45 to 54 | 12.9% | 11.7% | 12.6% |
| Age 55 to 59 | 5.4% | 4.5% | 6.7% |
| Age 60 to 64 | 5.1% | 4.1% | 6.3% |
| Age 65 to 74 | 7.3% | 5.4% | 9.6% |
| Age 75 to 84 | 2.9% | 2.2% | 4.5% |
| Age 85 and over | 1.1% | 1.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Plainfield, NJ | Passaic, NJ | United States |
| White | 8.8% | 15.7% | 59.4% |
| Black | 35.9% | 6.4% | 12.2% |
| Asian | 1.0% | 3.6% | 5.6% |
| Native American | 0.1% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.6% | 0.3% | 0.4% |
| Two or More Races | 1.5% | 0.4% | 3.2% |
| Hispanic | 51.3% | 73.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Plainfield, NJ | Passaic, NJ | United States |
| Married Population | 38.7% | 37.3% | 49.8% |
| Currently Married | 36.6% | 33.5% | 48.0% |
| Married but Separated | 2.1% | 3.9% | 1.8% |
| Single Population | 61.3% | 62.7% | 50.2% |
| Never Married | 50.2% | 51.4% | 33.8% |
| Divorced | 7.2% | 7.6% | 10.8% |
| Widowed | 3.9% | 3.7% | 5.6% |
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| Household Size | 3.17 | 3.46 | 2.60 |
| Households | 16,693 | 20,217 | 124,010,992 |
| Family Households | 12,076 | 15,515 | 80,755,759 |
| Married couple, w/children | 27.6% | 28.6% | 30.5% |
| Married couple, no children | 27.0% | 18.5% | 42.9% |
| Non Family Households | 4,617 | 4,702 | 43,255,233 |
| Single householder, w/children | 29.3% | 35.3% | 15.8% |
| Single householder, no children | 16.1% | 17.6% | 10.8% |