| | Kooskia, ID | Elk River, ID | United States |
| Population | 596 | 121 | 329,725,481 |
| Female Population | 50.2% | 50.4% | 50.5% |
| Male Population | 49.8% | 49.6% | 49.5% |
| Median Age | 56.1 | 58.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 655 | 124 | 309,327,143 |
| Population - 2000 | 675 | 156 | 285,036,114 |
| Population - 1990 | 692 | 149 | 251,960,433 |
| Pop. 2000 to Now | 0.3% | -21.2% | 15.6% |
| Pop. 1990 to Now | -2.2% | -17.5% | 30.8% |
| space4 | | | |
| Population Density | 941.6 | 834.5 | 93.4 |
| Land Area | 0.6 | 0.1 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Kooskia, ID | Elk River, ID | United States |
| Age 0 to 4 | 5.0% | 1.7% | 5.9% |
| Age 5 to 9 | 5.9% | 0.0% | 6.1% |
| Age 10 to 14 | 3.4% | 3.3% | 6.6% |
| Age 15 to 17 | 7.7% | 1.7% | 3.9% |
| Age 18 to 20 | 0.7% | 0.0% | 4.0% |
| Age 21 to 24 | 1.8% | 4.1% | 5.2% |
| Age 25 to 34 | 8.7% | 6.6% | 13.8% |
| Age 35 to 44 | 6.2% | 5.8% | 12.9% |
| Age 45 to 54 | 4.7% | 9.9% | 12.6% |
| Age 55 to 59 | 12.6% | 19.0% | 6.7% |
| Age 60 to 64 | 7.6% | 9.9% | 6.3% |
| Age 65 to 74 | 27.9% | 21.5% | 9.6% |
| Age 75 to 84 | 6.9% | 10.7% | 4.5% |
| Age 85 and over | 1.0% | 5.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Kooskia, ID | Elk River, ID | United States |
| White | 72.8% | 98.3% | 59.4% |
| Black | 0.3% | 0.0% | 12.2% |
| Asian | 1.5% | 0.0% | 5.6% |
| Native American | 21.3% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.7% | 1.7% | 3.2% |
| Hispanic | 3.4% | 0.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Kooskia, ID | Elk River, ID | United States |
| Married Population | 52.1% | 60.0% | 49.8% |
| Currently Married | 48.7% | 57.4% | 48.0% |
| Married but Separated | 3.3% | 2.6% | 1.8% |
| Single Population | 47.9% | 40.0% | 50.2% |
| Never Married | 17.0% | 1.7% | 33.8% |
| Divorced | 16.8% | 27.0% | 10.8% |
| Widowed | 14.1% | 11.3% | 5.6% |
| space5 | | | |
| Household Size | 2.61 | 2.02 | 2.60 |
| Households | 228 | 60 | 124,010,992 |
| Family Households | 126 | 34 | 80,755,759 |
| Married couple, w/children | 23.0% | 5.9% | 30.5% |
| Married couple, no children | 50.0% | 76.5% | 42.9% |
| Non Family Households | 102 | 26 | 43,255,233 |
| Single householder, w/children | 20.6% | 17.6% | 15.8% |
| Single householder, no children | 6.3% | 0.0% | 10.8% |