| | Hazlet, NJ | Old Bridge township, NJ | United States |
| Population | 20,193 | 66,925 | 329,725,481 |
| Female Population | 51.8% | 50.7% | 50.5% |
| Male Population | 48.2% | 49.3% | 49.5% |
| Median Age | 44.1 | 42.8 | 38.4 |
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| Population - 2010 | 20,317 | 65,399 | 309,327,143 |
| Population - 2000 | 21,378 | 60,456 | 285,036,114 |
| Population - 1990 | 21,976 | 56,475 | 251,960,433 |
| Pop. 2000 to Now | -8.1% | 8.2% | 15.6% |
| Pop. 1990 to Now | -10.6% | 15.8% | 30.8% |
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| Population Density | 3,627.3 | 1,758.4 | 93.4 |
| Land Area | 5.6 | 38.1 | 3,531,905.4 |
| Water Area | 0.1 | 2.7 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Hazlet, NJ | Old Bridge township, NJ | United States |
| Age 0 to 4 | 5.0% | 4.5% | 5.9% |
| Age 5 to 9 | 4.6% | 5.5% | 6.1% |
| Age 10 to 14 | 6.1% | 5.6% | 6.6% |
| Age 15 to 17 | 4.2% | 4.1% | 3.9% |
| Age 18 to 20 | 3.3% | 2.9% | 4.0% |
| Age 21 to 24 | 5.2% | 3.7% | 5.2% |
| Age 25 to 34 | 12.3% | 13.1% | 13.8% |
| Age 35 to 44 | 10.8% | 13.3% | 12.9% |
| Age 45 to 54 | 14.5% | 14.4% | 12.6% |
| Age 55 to 59 | 8.3% | 9.1% | 6.7% |
| Age 60 to 64 | 6.8% | 6.8% | 6.3% |
| Age 65 to 74 | 10.3% | 10.3% | 9.6% |
| Age 75 to 84 | 5.1% | 4.7% | 4.5% |
| Age 85 and over | 3.6% | 1.9% | 1.9% |
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| Race | | | |
| | Hazlet, NJ | Old Bridge township, NJ | United States |
| White | 81.0% | 60.2% | 59.4% |
| Black | 1.8% | 6.8% | 12.2% |
| Asian | 2.5% | 15.0% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.9% | 0.1% | 0.4% |
| Two or More Races | 2.7% | 3.2% | 3.2% |
| Hispanic | 11.1% | 14.6% | 18.4% |
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| Marriage & Family | | | |
| | Hazlet, NJ | Old Bridge township, NJ | United States |
| Married Population | 53.7% | 56.3% | 49.8% |
| Currently Married | 52.6% | 54.9% | 48.0% |
| Married but Separated | 1.1% | 1.4% | 1.8% |
| Single Population | 46.3% | 43.7% | 50.2% |
| Never Married | 29.4% | 29.2% | 33.8% |
| Divorced | 7.4% | 8.0% | 10.8% |
| Widowed | 9.5% | 6.5% | 5.6% |
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| Household Size | 2.74 | 2.59 | 2.60 |
| Households | 7,299 | 25,661 | 124,010,992 |
| Family Households | 5,259 | 17,657 | 80,755,759 |
| Married couple, w/children | 34.6% | 33.7% | 30.5% |
| Married couple, no children | 45.3% | 47.6% | 42.9% |
| Non Family Households | 2,040 | 8,004 | 43,255,233 |
| Single householder, w/children | 8.2% | 8.0% | 15.8% |
| Single householder, no children | 12.0% | 10.7% | 10.8% |