| | Chester, NH | Chelsea, MA | United States |
| Population | 5,198 | 40,025 | 329,725,481 |
| Female Population | 47.9% | 48.8% | 50.5% |
| Male Population | 52.1% | 51.3% | 49.5% |
| Median Age | 46.4 | 33.6 | 38.4 |
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| Population - 2010 | 4,776 | 35,344 | 309,327,143 |
| Population - 2000 | 3,792 | 35,080 | 285,036,114 |
| Population - 1990 | 2,691 | 28,710 | 251,960,433 |
| Pop. 2000 to Now | 39.2% | 11.8% | 15.6% |
| Pop. 1990 to Now | 96.1% | 36.6% | 30.8% |
| space4 | | | |
| Population Density | 200.5 | 18,070.0 | 93.4 |
| Land Area | 25.9 | 2.2 | 3,531,905.4 |
| Water Area | 0.1 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Chester, NH | Chelsea, MA | United States |
| Age 0 to 4 | 5.2% | 8.5% | 5.9% |
| Age 5 to 9 | 5.2% | 5.5% | 6.1% |
| Age 10 to 14 | 5.8% | 7.2% | 6.6% |
| Age 15 to 17 | 3.9% | 4.1% | 3.9% |
| Age 18 to 20 | 4.6% | 3.5% | 4.0% |
| Age 21 to 24 | 6.1% | 4.9% | 5.2% |
| Age 25 to 34 | 8.5% | 18.9% | 13.8% |
| Age 35 to 44 | 9.9% | 15.8% | 12.9% |
| Age 45 to 54 | 16.2% | 11.7% | 12.6% |
| Age 55 to 59 | 12.1% | 5.3% | 6.7% |
| Age 60 to 64 | 9.3% | 5.1% | 6.3% |
| Age 65 to 74 | 8.1% | 5.4% | 9.6% |
| Age 75 to 84 | 5.2% | 2.5% | 4.5% |
| Age 85 and over | 0.1% | 1.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Chester, NH | Chelsea, MA | United States |
| White | 96.9% | 19.7% | 59.4% |
| Black | 0.2% | 7.0% | 12.2% |
| Asian | 1.1% | 3.5% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 0.0% | 3.3% | 3.2% |
| Hispanic | 1.8% | 66.1% | 18.4% |
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| Marriage & Family | | | |
| | Chester, NH | Chelsea, MA | United States |
| Married Population | 62.7% | 41.5% | 49.8% |
| Currently Married | 61.7% | 36.9% | 48.0% |
| Married but Separated | 1.0% | 4.6% | 1.8% |
| Single Population | 37.3% | 58.5% | 50.2% |
| Never Married | 26.7% | 44.7% | 33.8% |
| Divorced | 8.3% | 8.4% | 10.8% |
| Widowed | 2.3% | 5.5% | 5.6% |
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| Household Size | 3.01 | 2.94 | 2.60 |
| Households | 1,719 | 13,353 | 124,010,992 |
| Family Households | 1,446 | 7,470 | 80,755,759 |
| Married couple, w/children | 33.7% | 34.0% | 30.5% |
| Married couple, no children | 54.1% | 26.6% | 42.9% |
| Non Family Households | 273 | 5,883 | 43,255,233 |
| Single householder, w/children | 7.5% | 25.3% | 15.8% |
| Single householder, no children | 4.7% | 14.1% | 10.8% |