| | Williamson, NY | Geneva, NY | United States |
| Population | 6,869 | 12,577 | 329,725,481 |
| Female Population | 49.2% | 51.9% | 50.5% |
| Male Population | 50.8% | 48.1% | 49.5% |
| Median Age | 43.1 | 30.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 6,996 | 13,205 | 309,327,143 |
| Population - 2000 | 6,777 | 13,617 | 285,036,114 |
| Population - 1990 | 6,540 | 14,143 | 251,960,433 |
| Pop. 2000 to Now | -1.3% | -7.2% | 15.6% |
| Pop. 1990 to Now | 2.3% | -10.6% | 30.8% |
| space4 | | | |
| Population Density | 198.3 | 2,987.4 | 93.4 |
| Land Area | 34.6 | 4.2 | 3,531,905.4 |
| Water Area | 0.0 | 1.6 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Williamson, NY | Geneva, NY | United States |
| Age 0 to 4 | 6.5% | 6.2% | 5.9% |
| Age 5 to 9 | 4.4% | 4.9% | 6.1% |
| Age 10 to 14 | 4.4% | 3.2% | 6.6% |
| Age 15 to 17 | 3.8% | 2.8% | 3.9% |
| Age 18 to 20 | 1.9% | 15.6% | 4.0% |
| Age 21 to 24 | 7.1% | 10.7% | 5.2% |
| Age 25 to 34 | 15.2% | 12.0% | 13.8% |
| Age 35 to 44 | 7.8% | 6.5% | 12.9% |
| Age 45 to 54 | 14.1% | 10.9% | 12.6% |
| Age 55 to 59 | 8.3% | 5.7% | 6.7% |
| Age 60 to 64 | 7.2% | 6.7% | 6.3% |
| Age 65 to 74 | 11.5% | 9.0% | 9.6% |
| Age 75 to 84 | 5.8% | 4.4% | 4.5% |
| Age 85 and over | 1.8% | 1.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Williamson, NY | Geneva, NY | United States |
| White | 88.9% | 71.7% | 59.4% |
| Black | 1.8% | 6.8% | 12.2% |
| Asian | 0.1% | 3.0% | 5.6% |
| Native American | 0.1% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.0% | 0.4% |
| Two or More Races | 3.7% | 3.5% | 3.2% |
| Hispanic | 5.3% | 14.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Williamson, NY | Geneva, NY | United States |
| Married Population | 53.4% | 30.9% | 49.8% |
| Currently Married | 52.0% | 28.3% | 48.0% |
| Married but Separated | 1.4% | 2.6% | 1.8% |
| Single Population | 46.6% | 69.1% | 50.2% |
| Never Married | 29.6% | 51.2% | 33.8% |
| Divorced | 12.3% | 12.9% | 10.8% |
| Widowed | 4.7% | 5.0% | 5.6% |
| space5 | | | |
| Household Size | 2.32 | 2.22 | 2.60 |
| Households | 2,898 | 4,655 | 124,010,992 |
| Family Households | 1,936 | 2,350 | 80,755,759 |
| Married couple, w/children | 18.5% | 22.0% | 30.5% |
| Married couple, no children | 56.7% | 33.9% | 42.9% |
| Non Family Households | 962 | 2,305 | 43,255,233 |
| Single householder, w/children | 16.6% | 24.2% | 15.8% |
| Single householder, no children | 8.2% | 19.9% | 10.8% |