| | Prospect, NY | De Witt, NY | United States |
| Population | 354 | 25,920 | 329,725,481 |
| Female Population | 52.8% | 49.7% | 50.5% |
| Male Population | 47.2% | 50.3% | 49.5% |
| Median Age | 44.7 | 42.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 287 | 25,911 | 309,327,143 |
| Population - 2000 | 330 | 24,071 | 285,036,114 |
| Population - 1990 | 312 | 25,148 | 251,960,433 |
| Pop. 2000 to Now | -6.4% | 3.7% | 15.6% |
| Pop. 1990 to Now | -1.0% | -0.7% | 30.8% |
| space4 | | | |
| Population Density | 823.3 | 767.5 | 93.4 |
| Land Area | 0.4 | 33.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Prospect, NY | De Witt, NY | United States |
| Age 0 to 4 | 4.8% | 4.7% | 5.9% |
| Age 5 to 9 | 12.7% | 6.1% | 6.1% |
| Age 10 to 14 | 10.2% | 6.5% | 6.6% |
| Age 15 to 17 | 6.5% | 3.5% | 3.9% |
| Age 18 to 20 | 0.0% | 5.3% | 4.0% |
| Age 21 to 24 | 3.4% | 4.5% | 5.2% |
| Age 25 to 34 | 0.0% | 11.6% | 13.8% |
| Age 35 to 44 | 14.4% | 10.4% | 12.9% |
| Age 45 to 54 | 19.8% | 13.5% | 12.6% |
| Age 55 to 59 | 2.0% | 7.1% | 6.7% |
| Age 60 to 64 | 0.0% | 7.9% | 6.3% |
| Age 65 to 74 | 14.7% | 10.5% | 9.6% |
| Age 75 to 84 | 9.6% | 5.4% | 4.5% |
| Age 85 and over | 2.0% | 2.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Prospect, NY | De Witt, NY | United States |
| White | 84.2% | 78.8% | 59.4% |
| Black | 13.6% | 7.5% | 12.2% |
| Asian | 0.0% | 4.0% | 5.6% |
| Native American | 0.0% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 2.3% | 5.5% | 3.2% |
| Hispanic | 0.0% | 3.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Prospect, NY | De Witt, NY | United States |
| Married Population | 57.8% | 48.2% | 49.8% |
| Currently Married | 57.8% | 46.8% | 48.0% |
| Married but Separated | 0.0% | 1.4% | 1.8% |
| Single Population | 42.2% | 51.8% | 50.2% |
| Never Married | 16.4% | 35.8% | 33.8% |
| Divorced | 18.4% | 9.8% | 10.8% |
| Widowed | 7.4% | 6.2% | 5.6% |
| space5 | | | |
| Household Size | 3.34 | 2.39 | 2.60 |
| Households | 106 | 10,181 | 124,010,992 |
| Family Households | 84 | 6,022 | 80,755,759 |
| Married couple, w/children | 40.5% | 32.5% | 30.5% |
| Married couple, no children | 23.8% | 43.8% | 42.9% |
| Non Family Households | 22 | 4,159 | 43,255,233 |
| Single householder, w/children | 16.7% | 13.1% | 15.8% |
| Single householder, no children | 19.0% | 10.6% | 10.8% |