| | Mason, NH | Brookline, NH | United States |
| Population | 1,474 | 5,591 | 329,725,481 |
| Female Population | 45.4% | 52.4% | 50.5% |
| Male Population | 54.6% | 47.6% | 49.5% |
| Median Age | 42.5 | 38.8 | 38.4 |
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| Population - 2010 | 1,387 | 4,999 | 309,327,143 |
| Population - 2000 | 1,147 | 4,181 | 285,036,114 |
| Population - 1990 | 1,212 | 2,410 | 251,960,433 |
| Pop. 2000 to Now | 24.9% | 31.4% | 15.6% |
| Pop. 1990 to Now | 18.2% | 128.0% | 30.8% |
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| Population Density | 61.7 | 282.8 | 93.4 |
| Land Area | 23.9 | 19.8 | 3,531,905.4 |
| Water Area | 0.1 | 0.4 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Mason, NH | Brookline, NH | United States |
| Age 0 to 4 | 6.7% | 5.2% | 5.9% |
| Age 5 to 9 | 6.6% | 7.7% | 6.1% |
| Age 10 to 14 | 7.5% | 7.5% | 6.6% |
| Age 15 to 17 | 6.0% | 7.0% | 3.9% |
| Age 18 to 20 | 1.6% | 5.8% | 4.0% |
| Age 21 to 24 | 4.5% | 4.6% | 5.2% |
| Age 25 to 34 | 9.5% | 6.6% | 13.8% |
| Age 35 to 44 | 11.6% | 14.6% | 12.9% |
| Age 45 to 54 | 11.3% | 14.5% | 12.6% |
| Age 55 to 59 | 11.5% | 12.9% | 6.7% |
| Age 60 to 64 | 9.5% | 6.1% | 6.3% |
| Age 65 to 74 | 10.2% | 5.7% | 9.6% |
| Age 75 to 84 | 2.8% | 1.8% | 4.5% |
| Age 85 and over | 0.6% | 0.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Mason, NH | Brookline, NH | United States |
| White | 90.5% | 94.9% | 59.4% |
| Black | 0.0% | 0.6% | 12.2% |
| Asian | 1.2% | 0.4% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.0% | 2.2% | 3.2% |
| Hispanic | 7.3% | 1.9% | 18.4% |
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| Marriage & Family | | | |
| | Mason, NH | Brookline, NH | United States |
| Married Population | 53.9% | 66.1% | 49.8% |
| Currently Married | 53.6% | 66.1% | 48.0% |
| Married but Separated | 0.3% | 0.0% | 1.8% |
| Single Population | 46.1% | 33.9% | 50.2% |
| Never Married | 28.2% | 26.4% | 33.8% |
| Divorced | 13.0% | 6.2% | 10.8% |
| Widowed | 4.9% | 1.4% | 5.6% |
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| Household Size | 2.67 | 3.24 | 2.60 |
| Households | 552 | 1,728 | 124,010,992 |
| Family Households | 366 | 1,542 | 80,755,759 |
| Married couple, w/children | 30.3% | 50.6% | 30.5% |
| Married couple, no children | 54.1% | 39.0% | 42.9% |
| Non Family Households | 186 | 186 | 43,255,233 |
| Single householder, w/children | 13.7% | 6.6% | 15.8% |
| Single householder, no children | 1.9% | 3.8% | 10.8% |