| | Greenville, CA | Geneva, AL | United States |
| Population | 648 | 4,208 | 329,725,481 |
| Female Population | 44.3% | 53.2% | 50.5% |
| Male Population | 55.7% | 46.8% | 49.5% |
| Median Age | 51.2 | 50.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 994 | 4,422 | 309,327,143 |
| Population - 2000 | 1,160 | 4,388 | 285,036,114 |
| Population - 1990 | 1,396 | 4,681 | 251,960,433 |
| Pop. 2000 to Now | -21.0% | -2.9% | 15.6% |
| Pop. 1990 to Now | -34.4% | -9.0% | 30.8% |
| space4 | | | |
| Population Density | 81.1 | 265.1 | 93.4 |
| Land Area | 8.0 | 15.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Greenville, CA | Geneva, AL | United States |
| Age 0 to 4 | 0.0% | 4.3% | 5.9% |
| Age 5 to 9 | 5.9% | 7.2% | 6.1% |
| Age 10 to 14 | 0.0% | 3.3% | 6.6% |
| Age 15 to 17 | 11.0% | 2.9% | 3.9% |
| Age 18 to 20 | 0.0% | 2.2% | 4.0% |
| Age 21 to 24 | 0.9% | 1.0% | 5.2% |
| Age 25 to 34 | 15.1% | 14.0% | 13.8% |
| Age 35 to 44 | 2.5% | 5.7% | 12.9% |
| Age 45 to 54 | 17.3% | 17.3% | 12.6% |
| Age 55 to 59 | 6.2% | 6.3% | 6.7% |
| Age 60 to 64 | 7.1% | 11.5% | 6.3% |
| Age 65 to 74 | 30.6% | 12.2% | 9.6% |
| Age 75 to 84 | 2.3% | 10.1% | 4.5% |
| Age 85 and over | 1.2% | 1.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Greenville, CA | Geneva, AL | United States |
| White | 80.4% | 78.9% | 59.4% |
| Black | 0.6% | 11.5% | 12.2% |
| Asian | 7.6% | 3.3% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 8.5% | 0.1% | 3.2% |
| Hispanic | 2.9% | 6.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Greenville, CA | Geneva, AL | United States |
| Married Population | 28.5% | 45.8% | 49.8% |
| Currently Married | 28.5% | 42.4% | 48.0% |
| Married but Separated | 0.0% | 3.4% | 1.8% |
| Single Population | 71.5% | 54.2% | 50.2% |
| Never Married | 38.7% | 27.4% | 33.8% |
| Divorced | 16.7% | 19.6% | 10.8% |
| Widowed | 16.1% | 7.3% | 5.6% |
| space5 | | | |
| Household Size | 1.98 | 2.10 | 2.60 |
| Households | 325 | 1,933 | 124,010,992 |
| Family Households | 131 | 1,068 | 80,755,759 |
| Married couple, w/children | 0.0% | 26.7% | 30.5% |
| Married couple, no children | 46.6% | 48.7% | 42.9% |
| Non Family Households | 194 | 865 | 43,255,233 |
| Single householder, w/children | 40.5% | 13.8% | 15.8% |
| Single householder, no children | 13.0% | 10.9% | 10.8% |