| | Washington, CT | Millbrook, NY | United States |
| Population | 3,619 | 1,364 | 329,725,481 |
| Female Population | 52.6% | 53.0% | 50.5% |
| Male Population | 47.4% | 47.0% | 49.5% |
| Median Age | 48.8 | 56 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,576 | 1,453 | 309,327,143 |
| Population - 2000 | 3,596 | 1,429 | 285,036,114 |
| Population - 1990 | 3,905 | 1,339 | 251,960,433 |
| Pop. 2000 to Now | -4.9% | -2.8% | 15.6% |
| Pop. 1990 to Now | -12.5% | 3.7% | 30.8% |
| space4 | | | |
| Population Density | 95.1 | 733.3 | 93.4 |
| Land Area | 38.1 | 1.9 | 3,531,905.4 |
| Water Area | 0.6 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Washington, CT | Millbrook, NY | United States |
| Age 0 to 4 | 4.9% | 4.5% | 5.9% |
| Age 5 to 9 | 3.4% | 0.3% | 6.1% |
| Age 10 to 14 | 5.9% | 1.4% | 6.6% |
| Age 15 to 17 | 3.8% | 5.4% | 3.9% |
| Age 18 to 20 | 4.3% | 1.2% | 4.0% |
| Age 21 to 24 | 3.0% | 3.0% | 5.2% |
| Age 25 to 34 | 12.7% | 9.8% | 13.8% |
| Age 35 to 44 | 7.8% | 10.0% | 12.9% |
| Age 45 to 54 | 9.9% | 13.0% | 12.6% |
| Age 55 to 59 | 7.5% | 9.5% | 6.7% |
| Age 60 to 64 | 7.9% | 10.3% | 6.3% |
| Age 65 to 74 | 21.4% | 11.4% | 9.6% |
| Age 75 to 84 | 5.0% | 14.9% | 4.5% |
| Age 85 and over | 2.3% | 5.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Washington, CT | Millbrook, NY | United States |
| White | 83.4% | 85.3% | 59.4% |
| Black | 1.4% | 2.9% | 12.2% |
| Asian | 1.7% | 5.5% | 5.6% |
| Native American | 0.0% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.0% | 0.4% |
| Two or More Races | 1.3% | 1.0% | 3.2% |
| Hispanic | 12.0% | 5.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Washington, CT | Millbrook, NY | United States |
| Married Population | 55.3% | 48.9% | 49.8% |
| Currently Married | 52.6% | 46.9% | 48.0% |
| Married but Separated | 2.6% | 2.0% | 1.8% |
| Single Population | 44.7% | 51.1% | 50.2% |
| Never Married | 24.9% | 30.0% | 33.8% |
| Divorced | 14.4% | 12.4% | 10.8% |
| Widowed | 5.4% | 8.6% | 5.6% |
| space5 | | | |
| Household Size | 2.35 | 1.85 | 2.60 |
| Households | 1,423 | 733 | 124,010,992 |
| Family Households | 928 | 321 | 80,755,759 |
| Married couple, w/children | 28.0% | 16.5% | 30.5% |
| Married couple, no children | 51.9% | 62.0% | 42.9% |
| Non Family Households | 495 | 412 | 43,255,233 |
| Single householder, w/children | 16.2% | 10.9% | 15.8% |
| Single householder, no children | 3.9% | 10.6% | 10.8% |