| | Rock River, WY | Downey, ID | United States |
| Population | 244 | 764 | 329,725,481 |
| Female Population | 38.5% | 51.4% | 50.5% |
| Male Population | 61.5% | 48.6% | 49.5% |
| Median Age | 29.6 | 36.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 246 | 626 | 309,327,143 |
| Population - 2000 | 235 | 613 | 285,036,114 |
| Population - 1990 | 190 | 626 | 251,960,433 |
| Pop. 2000 to Now | 10.2% | 3.4% | 15.6% |
| Pop. 1990 to Now | 36.3% | 1.3% | 30.8% |
| space4 | | | |
| Population Density | 104.9 | 781.2 | 93.4 |
| Land Area | 2.3 | 1.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Rock River, WY | Downey, ID | United States |
| Age 0 to 4 | 1.6% | 3.3% | 5.9% |
| Age 5 to 9 | 5.3% | 10.1% | 6.1% |
| Age 10 to 14 | 6.1% | 12.7% | 6.6% |
| Age 15 to 17 | 3.3% | 4.1% | 3.9% |
| Age 18 to 20 | 0.0% | 2.4% | 4.0% |
| Age 21 to 24 | 15.6% | 3.7% | 5.2% |
| Age 25 to 34 | 24.6% | 11.8% | 13.8% |
| Age 35 to 44 | 12.7% | 12.4% | 12.9% |
| Age 45 to 54 | 4.9% | 4.8% | 12.6% |
| Age 55 to 59 | 2.0% | 7.3% | 6.7% |
| Age 60 to 64 | 2.0% | 6.9% | 6.3% |
| Age 65 to 74 | 15.2% | 12.4% | 9.6% |
| Age 75 to 84 | 2.5% | 6.9% | 4.5% |
| Age 85 and over | 4.1% | 1.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Rock River, WY | Downey, ID | United States |
| White | 79.9% | 91.2% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 2.5% | 0.0% | 5.6% |
| Native American | 0.0% | 2.9% | 0.6% |
| Hawaiian, Pacific Islander | 4.5% | 0.9% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.0% | 2.7% | 3.2% |
| Hispanic | 13.1% | 2.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Rock River, WY | Downey, ID | United States |
| Married Population | 35.8% | 57.5% | 49.8% |
| Currently Married | 35.8% | 55.8% | 48.0% |
| Married but Separated | 0.0% | 1.8% | 1.8% |
| Single Population | 64.2% | 42.5% | 50.2% |
| Never Married | 52.4% | 21.8% | 33.8% |
| Divorced | 0.0% | 10.4% | 10.8% |
| Widowed | 11.8% | 10.3% | 5.6% |
| space5 | | | |
| Household Size | 2.52 | 2.64 | 2.60 |
| Households | 97 | 287 | 124,010,992 |
| Family Households | 40 | 181 | 80,755,759 |
| Married couple, w/children | 40.0% | 34.8% | 30.5% |
| Married couple, no children | 47.5% | 42.5% | 42.9% |
| Non Family Households | 57 | 106 | 43,255,233 |
| Single householder, w/children | 0.0% | 14.9% | 15.8% |
| Single householder, no children | 12.5% | 7.7% | 10.8% |