| | Brunswick, ME | Ithaca, NY | United States |
| Population | 21,589 | 31,819 | 329,725,481 |
| Female Population | 51.4% | 49.2% | 50.5% |
| Male Population | 48.6% | 50.8% | 49.5% |
| Median Age | 42.8 | 22.3 | 38.4 |
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| Population - 2010 | 20,256 | 30,046 | 309,327,143 |
| Population - 2000 | 21,172 | 29,287 | 285,036,114 |
| Population - 1990 | 20,906 | 29,541 | 251,960,433 |
| Pop. 2000 to Now | -2.6% | 5.8% | 15.6% |
| Pop. 1990 to Now | -1.4% | 4.9% | 30.8% |
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| Population Density | 462.0 | 5,904.4 | 93.4 |
| Land Area | 46.7 | 5.4 | 3,531,905.4 |
| Water Area | 7.6 | 0.7 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Brunswick, ME | Ithaca, NY | United States |
| Age 0 to 4 | 5.8% | 1.8% | 5.9% |
| Age 5 to 9 | 4.7% | 1.9% | 6.1% |
| Age 10 to 14 | 4.0% | 2.2% | 6.6% |
| Age 15 to 17 | 3.4% | 1.7% | 3.9% |
| Age 18 to 20 | 6.9% | 28.2% | 4.0% |
| Age 21 to 24 | 7.0% | 23.4% | 5.2% |
| Age 25 to 34 | 9.5% | 12.4% | 13.8% |
| Age 35 to 44 | 10.7% | 9.4% | 12.9% |
| Age 45 to 54 | 13.1% | 5.8% | 12.6% |
| Age 55 to 59 | 7.0% | 3.4% | 6.7% |
| Age 60 to 64 | 7.1% | 3.2% | 6.3% |
| Age 65 to 74 | 11.4% | 3.7% | 9.6% |
| Age 75 to 84 | 6.6% | 1.6% | 4.5% |
| Age 85 and over | 2.9% | 1.3% | 1.9% |
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| Race | | | |
| | Brunswick, ME | Ithaca, NY | United States |
| White | 89.6% | 64.1% | 59.4% |
| Black | 1.9% | 4.5% | 12.2% |
| Asian | 1.6% | 16.1% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.9% | 0.4% |
| Two or More Races | 3.3% | 6.0% | 3.2% |
| Hispanic | 3.2% | 8.4% | 18.4% |
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| Marriage & Family | | | |
| | Brunswick, ME | Ithaca, NY | United States |
| Married Population | 47.4% | 20.0% | 49.8% |
| Currently Married | 46.9% | 19.0% | 48.0% |
| Married but Separated | 0.5% | 1.0% | 1.8% |
| Single Population | 52.6% | 80.0% | 50.2% |
| Never Married | 32.6% | 73.7% | 33.8% |
| Divorced | 14.2% | 4.2% | 10.8% |
| Widowed | 5.9% | 2.0% | 5.6% |
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| Household Size | 2.29 | 1.93 | 2.60 |
| Households | 8,716 | 12,547 | 124,010,992 |
| Family Households | 5,020 | 3,451 | 80,755,759 |
| Married couple, w/children | 32.6% | 30.7% | 30.5% |
| Married couple, no children | 50.1% | 44.5% | 42.9% |
| Non Family Households | 3,696 | 9,096 | 43,255,233 |
| Single householder, w/children | 11.1% | 16.7% | 15.8% |
| Single householder, no children | 6.2% | 8.1% | 10.8% |