| | Derby, CT | Bridgeport, CT | United States |
| Population | 12,387 | 148,529 | 329,725,481 |
| Female Population | 55.0% | 52.0% | 50.5% |
| Male Population | 45.0% | 48.0% | 49.5% |
| Median Age | 46.8 | 34.9 | 38.4 |
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| Population - 2010 | 12,878 | 144,865 | 309,327,143 |
| Population - 2000 | 12,391 | 139,529 | 285,036,114 |
| Population - 1990 | 12,199 | 141,686 | 251,960,433 |
| Pop. 2000 to Now | -1.1% | 2.9% | 15.6% |
| Pop. 1990 to Now | 0.5% | 1.3% | 30.8% |
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| Population Density | 2,450.0 | 9,246.7 | 93.4 |
| Land Area | 5.1 | 16.1 | 3,531,905.4 |
| Water Area | 0.4 | 3.4 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Derby, CT | Bridgeport, CT | United States |
| Age 0 to 4 | 4.1% | 5.9% | 5.9% |
| Age 5 to 9 | 2.7% | 6.2% | 6.1% |
| Age 10 to 14 | 5.7% | 6.8% | 6.6% |
| Age 15 to 17 | 3.3% | 4.0% | 3.9% |
| Age 18 to 20 | 3.0% | 5.2% | 4.0% |
| Age 21 to 24 | 3.5% | 6.9% | 5.2% |
| Age 25 to 34 | 14.2% | 15.1% | 13.8% |
| Age 35 to 44 | 10.6% | 13.3% | 12.9% |
| Age 45 to 54 | 15.5% | 12.7% | 12.6% |
| Age 55 to 59 | 8.7% | 6.0% | 6.7% |
| Age 60 to 64 | 7.0% | 5.8% | 6.3% |
| Age 65 to 74 | 15.7% | 6.9% | 9.6% |
| Age 75 to 84 | 3.7% | 3.4% | 4.5% |
| Age 85 and over | 2.3% | 1.8% | 1.9% |
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| Race | | | |
| | Derby, CT | Bridgeport, CT | United States |
| White | 65.6% | 18.3% | 59.4% |
| Black | 8.8% | 32.1% | 12.2% |
| Asian | 1.6% | 4.3% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 3.5% | 1.2% | 0.4% |
| Two or More Races | 2.7% | 2.3% | 3.2% |
| Hispanic | 17.7% | 41.7% | 18.4% |
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| Marriage & Family | | | |
| | Derby, CT | Bridgeport, CT | United States |
| Married Population | 51.6% | 36.8% | 49.8% |
| Currently Married | 49.0% | 33.9% | 48.0% |
| Married but Separated | 2.6% | 3.0% | 1.8% |
| Single Population | 48.4% | 63.2% | 50.2% |
| Never Married | 27.3% | 46.6% | 33.8% |
| Divorced | 13.7% | 10.7% | 10.8% |
| Widowed | 7.5% | 5.9% | 5.6% |
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| Household Size | 2.18 | 2.72 | 2.60 |
| Households | 5,605 | 52,914 | 124,010,992 |
| Family Households | 3,459 | 33,365 | 80,755,759 |
| Married couple, w/children | 15.4% | 26.0% | 30.5% |
| Married couple, no children | 51.6% | 26.1% | 42.9% |
| Non Family Households | 2,146 | 19,549 | 43,255,233 |
| Single householder, w/children | 16.1% | 28.9% | 15.8% |
| Single householder, no children | 17.0% | 19.0% | 10.8% |