| | Green River, WY | Fond du Lac, WI | United States |
| Population | 11,887 | 44,412 | 329,725,481 |
| Female Population | 50.1% | 51.6% | 50.5% |
| Male Population | 50.0% | 48.4% | 49.5% |
| Median Age | 39.1 | 37.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 12,406 | 43,010 | 309,327,143 |
| Population - 2000 | 11,808 | 42,203 | 285,036,114 |
| Population - 1990 | 12,711 | 37,757 | 251,960,433 |
| Pop. 2000 to Now | -0.2% | 2.3% | 15.6% |
| Pop. 1990 to Now | -7.3% | 14.4% | 30.8% |
| space4 | | | |
| Population Density | 867.7 | 2,330.7 | 93.4 |
| Land Area | 13.7 | 19.1 | 3,531,905.4 |
| Water Area | 0.3 | 1.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Green River, WY | Fond du Lac, WI | United States |
| Age 0 to 4 | 5.5% | 5.9% | 5.9% |
| Age 5 to 9 | 8.0% | 6.4% | 6.1% |
| Age 10 to 14 | 9.0% | 7.3% | 6.6% |
| Age 15 to 17 | 4.8% | 3.2% | 3.9% |
| Age 18 to 20 | 3.0% | 4.6% | 4.0% |
| Age 21 to 24 | 2.2% | 5.8% | 5.2% |
| Age 25 to 34 | 12.8% | 13.0% | 13.8% |
| Age 35 to 44 | 13.9% | 14.4% | 12.9% |
| Age 45 to 54 | 14.5% | 11.5% | 12.6% |
| Age 55 to 59 | 5.9% | 6.5% | 6.7% |
| Age 60 to 64 | 7.1% | 5.6% | 6.3% |
| Age 65 to 74 | 8.9% | 8.7% | 9.6% |
| Age 75 to 84 | 2.9% | 4.3% | 4.5% |
| Age 85 and over | 1.6% | 2.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Green River, WY | Fond du Lac, WI | United States |
| White | 80.8% | 83.3% | 59.4% |
| Black | 0.0% | 3.4% | 12.2% |
| Asian | 0.8% | 2.2% | 5.6% |
| Native American | 1.8% | 0.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.2% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 1.9% | 2.4% | 3.2% |
| Hispanic | 14.7% | 7.6% | 18.4% |
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| Marriage & Family | | | |
| | Green River, WY | Fond du Lac, WI | United States |
| Married Population | 60.0% | 46.3% | 49.8% |
| Currently Married | 58.7% | 45.3% | 48.0% |
| Married but Separated | 1.3% | 1.0% | 1.8% |
| Single Population | 40.0% | 53.7% | 50.2% |
| Never Married | 21.5% | 34.7% | 33.8% |
| Divorced | 11.6% | 12.8% | 10.8% |
| Widowed | 6.9% | 6.3% | 5.6% |
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| Household Size | 2.76 | 2.31 | 2.60 |
| Households | 4,289 | 18,220 | 124,010,992 |
| Family Households | 3,136 | 10,424 | 80,755,759 |
| Married couple, w/children | 38.1% | 27.9% | 30.5% |
| Married couple, no children | 44.8% | 46.4% | 42.9% |
| Non Family Households | 1,153 | 7,796 | 43,255,233 |
| Single householder, w/children | 12.0% | 18.7% | 15.8% |
| Single householder, no children | 5.2% | 7.0% | 10.8% |