| | North Plainfield, NJ | Millburn, NJ | United States |
| Population | 22,635 | 21,637 | 329,725,481 |
| Female Population | 52.6% | 50.7% | 50.5% |
| Male Population | 47.4% | 49.3% | 49.5% |
| Median Age | 36.6 | 41.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 21,784 | 20,123 | 309,327,143 |
| Population - 2000 | 21,103 | 19,765 | 285,036,114 |
| Population - 1990 | 18,820 | 18,630 | 251,960,433 |
| Pop. 2000 to Now | 0.7% | 1.7% | 15.6% |
| Pop. 1990 to Now | 12.9% | 7.9% | 30.8% |
| space4 | | | |
| Population Density | 8,063.8 | 2,320.3 | 93.4 |
| Land Area | 2.8 | 9.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.6 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | North Plainfield, NJ | Millburn, NJ | United States |
| Age 0 to 4 | 7.6% | 5.8% | 5.9% |
| Age 5 to 9 | 6.0% | 8.4% | 6.1% |
| Age 10 to 14 | 6.2% | 11.3% | 6.6% |
| Age 15 to 17 | 3.3% | 6.1% | 3.9% |
| Age 18 to 20 | 3.6% | 1.9% | 4.0% |
| Age 21 to 24 | 5.2% | 2.4% | 5.2% |
| Age 25 to 34 | 15.0% | 5.6% | 13.8% |
| Age 35 to 44 | 14.2% | 15.3% | 12.9% |
| Age 45 to 54 | 12.1% | 18.2% | 12.6% |
| Age 55 to 59 | 8.0% | 6.4% | 6.7% |
| Age 60 to 64 | 7.5% | 5.2% | 6.3% |
| Age 65 to 74 | 7.6% | 8.5% | 9.6% |
| Age 75 to 84 | 2.2% | 3.6% | 4.5% |
| Age 85 and over | 1.3% | 1.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | North Plainfield, NJ | Millburn, NJ | United States |
| White | 22.9% | 54.6% | 59.4% |
| Black | 21.1% | 1.4% | 12.2% |
| Asian | 4.3% | 32.2% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.2% | 1.5% | 0.4% |
| Two or More Races | 1.0% | 3.5% | 3.2% |
| Hispanic | 49.5% | 6.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | North Plainfield, NJ | Millburn, NJ | United States |
| Married Population | 46.3% | 72.6% | 49.8% |
| Currently Married | 43.8% | 71.0% | 48.0% |
| Married but Separated | 2.5% | 1.5% | 1.8% |
| Single Population | 53.7% | 27.4% | 50.2% |
| Never Married | 42.8% | 19.9% | 33.8% |
| Divorced | 7.7% | 4.2% | 10.8% |
| Widowed | 3.2% | 3.3% | 5.6% |
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| Household Size | 2.82 | 3.03 | 2.60 |
| Households | 8,004 | 7,132 | 124,010,992 |
| Family Households | 5,599 | 6,066 | 80,755,759 |
| Married couple, w/children | 30.6% | 55.4% | 30.5% |
| Married couple, no children | 32.3% | 34.6% | 42.9% |
| Non Family Households | 2,405 | 1,066 | 43,255,233 |
| Single householder, w/children | 12.4% | 7.3% | 15.8% |
| Single householder, no children | 24.7% | 2.7% | 10.8% |