| | Mendon, MA | Exeter, NH | United States |
| Population | 6,212 | 15,847 | 329,725,481 |
| Female Population | 51.0% | 55.3% | 50.5% |
| Male Population | 49.0% | 44.7% | 49.5% |
| Median Age | 45.6 | 46.5 | 38.4 |
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| Population - 2010 | 5,859 | 14,301 | 309,327,143 |
| Population - 2000 | 5,286 | 14,058 | 285,036,114 |
| Population - 1990 | 4,010 | 12,481 | 251,960,433 |
| Pop. 2000 to Now | 17.9% | 8.8% | 15.6% |
| Pop. 1990 to Now | 55.4% | 22.6% | 30.8% |
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| Population Density | 349.5 | 810.3 | 93.4 |
| Land Area | 17.8 | 19.6 | 3,531,905.4 |
| Water Area | 0.2 | 0.4 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Mendon, MA | Exeter, NH | United States |
| Age 0 to 4 | 3.9% | 3.3% | 5.9% |
| Age 5 to 9 | 4.1% | 5.8% | 6.1% |
| Age 10 to 14 | 7.4% | 6.3% | 6.6% |
| Age 15 to 17 | 7.6% | 3.5% | 3.9% |
| Age 18 to 20 | 0.8% | 4.0% | 4.0% |
| Age 21 to 24 | 5.5% | 3.6% | 5.2% |
| Age 25 to 34 | 10.6% | 9.4% | 13.8% |
| Age 35 to 44 | 9.1% | 11.6% | 12.9% |
| Age 45 to 54 | 17.8% | 16.5% | 12.6% |
| Age 55 to 59 | 9.2% | 7.4% | 6.7% |
| Age 60 to 64 | 7.5% | 6.1% | 6.3% |
| Age 65 to 74 | 9.9% | 9.8% | 9.6% |
| Age 75 to 84 | 5.7% | 8.2% | 4.5% |
| Age 85 and over | 0.9% | 4.7% | 1.9% |
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| Race | | | |
| | Mendon, MA | Exeter, NH | United States |
| White | 92.8% | 89.9% | 59.4% |
| Black | 0.0% | 1.2% | 12.2% |
| Asian | 0.8% | 3.7% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 4.0% | 2.5% | 3.2% |
| Hispanic | 2.4% | 2.5% | 18.4% |
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| Marriage & Family | | | |
| | Mendon, MA | Exeter, NH | United States |
| Married Population | 65.9% | 50.6% | 49.8% |
| Currently Married | 63.0% | 49.9% | 48.0% |
| Married but Separated | 2.9% | 0.7% | 1.8% |
| Single Population | 34.1% | 49.4% | 50.2% |
| Never Married | 26.7% | 26.5% | 33.8% |
| Divorced | 3.9% | 14.3% | 10.8% |
| Widowed | 3.5% | 8.5% | 5.6% |
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| Household Size | 2.98 | 2.29 | 2.60 |
| Households | 2,076 | 6,739 | 124,010,992 |
| Family Households | 1,767 | 3,744 | 80,755,759 |
| Married couple, w/children | 41.2% | 36.2% | 30.5% |
| Married couple, no children | 50.4% | 47.9% | 42.9% |
| Non Family Households | 309 | 2,995 | 43,255,233 |
| Single householder, w/children | 3.0% | 9.4% | 15.8% |
| Single householder, no children | 5.4% | 6.5% | 10.8% |