| | Rochester, NH | Manchester, NH | United States |
| Population | 32,317 | 114,730 | 329,725,481 |
| Female Population | 49.4% | 49.7% | 50.5% |
| Male Population | 50.6% | 50.3% | 49.5% |
| Median Age | 42.6 | 36.9 | 38.4 |
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| Population - 2010 | 29,786 | 109,608 | 309,327,143 |
| Population - 2000 | 28,461 | 107,006 | 285,036,114 |
| Population - 1990 | 26,630 | 99,567 | 251,960,433 |
| Pop. 2000 to Now | 11.5% | 5.2% | 15.6% |
| Pop. 1990 to Now | 19.1% | 13.0% | 30.8% |
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| Population Density | 716.4 | 3,468.8 | 93.4 |
| Land Area | 45.1 | 33.1 | 3,531,905.4 |
| Water Area | 0.3 | 1.9 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Rochester, NH | Manchester, NH | United States |
| Age 0 to 4 | 4.3% | 5.5% | 5.9% |
| Age 5 to 9 | 6.3% | 5.2% | 6.1% |
| Age 10 to 14 | 6.1% | 5.1% | 6.6% |
| Age 15 to 17 | 3.9% | 3.1% | 3.9% |
| Age 18 to 20 | 4.4% | 3.3% | 4.0% |
| Age 21 to 24 | 4.3% | 6.2% | 5.2% |
| Age 25 to 34 | 12.0% | 18.6% | 13.8% |
| Age 35 to 44 | 12.4% | 13.5% | 12.9% |
| Age 45 to 54 | 13.4% | 12.3% | 12.6% |
| Age 55 to 59 | 8.6% | 6.6% | 6.7% |
| Age 60 to 64 | 6.9% | 6.8% | 6.3% |
| Age 65 to 74 | 10.5% | 7.5% | 9.6% |
| Age 75 to 84 | 4.1% | 4.3% | 4.5% |
| Age 85 and over | 2.8% | 2.1% | 1.9% |
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| Race | | | |
| | Rochester, NH | Manchester, NH | United States |
| White | 91.0% | 74.9% | 59.4% |
| Black | 1.0% | 5.3% | 12.2% |
| Asian | 1.7% | 4.9% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.5% | 0.0% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 3.3% | 3.5% | 3.2% |
| Hispanic | 2.6% | 11.0% | 18.4% |
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| Marriage & Family | | | |
| | Rochester, NH | Manchester, NH | United States |
| Married Population | 50.1% | 41.1% | 49.8% |
| Currently Married | 49.1% | 39.2% | 48.0% |
| Married but Separated | 1.0% | 1.8% | 1.8% |
| Single Population | 49.9% | 58.9% | 50.2% |
| Never Married | 28.6% | 39.2% | 33.8% |
| Divorced | 15.3% | 14.3% | 10.8% |
| Widowed | 6.1% | 5.4% | 5.6% |
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| Household Size | 2.39 | 2.32 | 2.60 |
| Households | 13,471 | 48,414 | 124,010,992 |
| Family Households | 8,476 | 25,967 | 80,755,759 |
| Married couple, w/children | 25.8% | 24.5% | 30.5% |
| Married couple, no children | 49.5% | 43.8% | 42.9% |
| Non Family Households | 4,995 | 22,447 | 43,255,233 |
| Single householder, w/children | 15.7% | 20.2% | 15.8% |
| Single householder, no children | 9.0% | 11.6% | 10.8% |