| | Chappaqua, NY | Menlo Park, CA | United States |
| Population | 3,062 | 33,677 | 329,725,481 |
| Female Population | 54.2% | 51.2% | 50.5% |
| Male Population | 45.8% | 48.8% | 49.5% |
| Median Age | 44.3 | 38.4 | 38.4 |
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| Population - 2010 | 1,040 | 32,083 | 309,327,143 |
| Population - 2000 | 9,468 | 30,785 | 285,036,114 |
| Population - 1990 | 1,274 | 28,040 | 251,960,433 |
| Pop. 2000 to Now | -86.3% | 13.5% | 15.6% |
| Pop. 1990 to Now | 1.6% | 24.6% | 30.8% |
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| Population Density | 6,700.2 | 3,363.7 | 93.4 |
| Land Area | 0.5 | 10.0 | 3,531,905.4 |
| Water Area | 0.0 | 7.4 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Chappaqua, NY | Menlo Park, CA | United States |
| Age 0 to 4 | 2.6% | 6.5% | 5.9% |
| Age 5 to 9 | 9.5% | 8.1% | 6.1% |
| Age 10 to 14 | 3.4% | 6.6% | 6.6% |
| Age 15 to 17 | 4.8% | 2.8% | 3.9% |
| Age 18 to 20 | 1.9% | 2.3% | 4.0% |
| Age 21 to 24 | 3.8% | 5.9% | 5.2% |
| Age 25 to 34 | 13.4% | 12.2% | 13.8% |
| Age 35 to 44 | 12.5% | 15.9% | 12.9% |
| Age 45 to 54 | 18.6% | 12.6% | 12.6% |
| Age 55 to 59 | 9.2% | 6.6% | 6.7% |
| Age 60 to 64 | 3.2% | 6.2% | 6.3% |
| Age 65 to 74 | 11.5% | 7.5% | 9.6% |
| Age 75 to 84 | 1.0% | 4.7% | 4.5% |
| Age 85 and over | 4.6% | 2.1% | 1.9% |
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| Race | | | |
| | Chappaqua, NY | Menlo Park, CA | United States |
| White | 81.6% | 55.6% | 59.4% |
| Black | 0.0% | 3.1% | 12.2% |
| Asian | 11.2% | 16.3% | 5.6% |
| Native American | 0.0% | 0.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 1.5% | 0.2% |
| Other | 0.9% | 0.3% | 0.4% |
| Two or More Races | 1.9% | 5.2% | 3.2% |
| Hispanic | 4.2% | 17.6% | 18.4% |
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| Marriage & Family | | | |
| | Chappaqua, NY | Menlo Park, CA | United States |
| Married Population | 55.8% | 56.5% | 49.8% |
| Currently Married | 55.8% | 55.6% | 48.0% |
| Married but Separated | 0.0% | 0.9% | 1.8% |
| Single Population | 44.2% | 43.5% | 50.2% |
| Never Married | 34.6% | 31.4% | 33.8% |
| Divorced | 7.1% | 8.4% | 10.8% |
| Widowed | 2.5% | 3.8% | 5.6% |
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| Household Size | 2.67 | 2.78 | 2.60 |
| Households | 1,143 | 11,725 | 124,010,992 |
| Family Households | 874 | 7,922 | 80,755,759 |
| Married couple, w/children | 35.5% | 43.2% | 30.5% |
| Married couple, no children | 46.6% | 41.3% | 42.9% |
| Non Family Households | 269 | 3,803 | 43,255,233 |
| Single householder, w/children | 8.1% | 8.4% | 15.8% |
| Single householder, no children | 9.8% | 7.1% | 10.8% |