| | Geneseo, NY | Jamestown, NY | United States |
| Population | 10,712 | 28,818 | 329,725,481 |
| Female Population | 57.0% | 50.9% | 50.5% |
| Male Population | 43.0% | 49.2% | 49.5% |
| Median Age | 21.6 | 36.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 10,504 | 31,079 | 309,327,143 |
| Population - 2000 | 9,654 | 31,730 | 285,036,114 |
| Population - 1990 | 9,178 | 34,681 | 251,960,433 |
| Pop. 2000 to Now | 8.3% | -9.0% | 15.6% |
| Pop. 1990 to Now | 13.9% | -16.8% | 30.8% |
| space4 | | | |
| Population Density | 243.8 | 3,225.7 | 93.4 |
| Land Area | 43.9 | 8.9 | 3,531,905.4 |
| Water Area | 1.2 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Geneseo, NY | Jamestown, NY | United States |
| Age 0 to 4 | 3.5% | 7.4% | 5.9% |
| Age 5 to 9 | 4.7% | 6.9% | 6.1% |
| Age 10 to 14 | 3.0% | 6.3% | 6.6% |
| Age 15 to 17 | 2.6% | 3.6% | 3.9% |
| Age 18 to 20 | 29.7% | 3.4% | 4.0% |
| Age 21 to 24 | 16.8% | 5.1% | 5.2% |
| Age 25 to 34 | 8.4% | 15.0% | 13.8% |
| Age 35 to 44 | 5.5% | 10.9% | 12.9% |
| Age 45 to 54 | 6.5% | 11.6% | 12.6% |
| Age 55 to 59 | 2.5% | 6.5% | 6.7% |
| Age 60 to 64 | 3.5% | 6.7% | 6.3% |
| Age 65 to 74 | 7.2% | 9.1% | 9.6% |
| Age 75 to 84 | 4.7% | 4.4% | 4.5% |
| Age 85 and over | 1.4% | 3.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Geneseo, NY | Jamestown, NY | United States |
| White | 87.3% | 82.3% | 59.4% |
| Black | 3.2% | 2.5% | 12.2% |
| Asian | 2.5% | 0.2% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.1% | 0.4% |
| Two or More Races | 2.0% | 4.1% | 3.2% |
| Hispanic | 4.9% | 10.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Geneseo, NY | Jamestown, NY | United States |
| Married Population | 28.3% | 36.4% | 49.8% |
| Currently Married | 27.4% | 33.5% | 48.0% |
| Married but Separated | 0.9% | 2.9% | 1.8% |
| Single Population | 71.7% | 63.6% | 50.2% |
| Never Married | 63.7% | 42.2% | 33.8% |
| Divorced | 4.0% | 14.7% | 10.8% |
| Widowed | 4.0% | 6.7% | 5.6% |
| space5 | | | |
| Household Size | 2.36 | 2.29 | 2.60 |
| Households | 3,114 | 12,313 | 124,010,992 |
| Family Households | 1,646 | 6,374 | 80,755,759 |
| Married couple, w/children | 26.4% | 22.1% | 30.5% |
| Married couple, no children | 50.1% | 32.0% | 42.9% |
| Non Family Households | 1,468 | 5,939 | 43,255,233 |
| Single householder, w/children | 17.6% | 31.1% | 15.8% |
| Single householder, no children | 5.9% | 14.8% | 10.8% |