| | John Day, OR | Post Falls, ID | United States |
| Population | 1,773 | 38,162 | 329,725,481 |
| Female Population | 48.5% | 52.1% | 50.5% |
| Male Population | 51.5% | 47.9% | 49.5% |
| Median Age | 43.1 | 34.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,756 | 27,950 | 309,327,143 |
| Population - 2000 | 1,821 | 17,247 | 285,036,114 |
| Population - 1990 | 1,836 | 7,349 | 251,960,433 |
| Pop. 2000 to Now | -8.4% | 125.7% | 15.6% |
| Pop. 1990 to Now | -9.1% | 429.8% | 30.8% |
| space4 | | | |
| Population Density | 822.7 | 2,613.1 | 93.4 |
| Land Area | 2.2 | 14.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | John Day, OR | Post Falls, ID | United States |
| Age 0 to 4 | 1.9% | 8.3% | 5.9% |
| Age 5 to 9 | 6.4% | 7.3% | 6.1% |
| Age 10 to 14 | 6.1% | 8.1% | 6.6% |
| Age 15 to 17 | 5.3% | 5.4% | 3.9% |
| Age 18 to 20 | 1.6% | 3.6% | 4.0% |
| Age 21 to 24 | 4.4% | 4.0% | 5.2% |
| Age 25 to 34 | 9.0% | 14.6% | 13.8% |
| Age 35 to 44 | 22.6% | 14.6% | 12.9% |
| Age 45 to 54 | 12.2% | 9.5% | 12.6% |
| Age 55 to 59 | 4.6% | 6.4% | 6.7% |
| Age 60 to 64 | 7.1% | 5.6% | 6.3% |
| Age 65 to 74 | 9.0% | 8.0% | 9.6% |
| Age 75 to 84 | 7.4% | 3.3% | 4.5% |
| Age 85 and over | 2.4% | 1.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | John Day, OR | Post Falls, ID | United States |
| White | 89.7% | 87.2% | 59.4% |
| Black | 0.0% | 0.2% | 12.2% |
| Asian | 1.6% | 0.6% | 5.6% |
| Native American | 2.2% | 0.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.3% | 0.1% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 3.5% | 5.2% | 3.2% |
| Hispanic | 2.7% | 6.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | John Day, OR | Post Falls, ID | United States |
| Married Population | 41.7% | 52.1% | 49.8% |
| Currently Married | 39.9% | 50.6% | 48.0% |
| Married but Separated | 1.8% | 1.5% | 1.8% |
| Single Population | 58.3% | 47.9% | 50.2% |
| Never Married | 27.6% | 28.0% | 33.8% |
| Divorced | 20.8% | 14.3% | 10.8% |
| Widowed | 9.8% | 5.7% | 5.6% |
| space5 | | | |
| Household Size | 2.13 | 2.84 | 2.60 |
| Households | 804 | 13,352 | 124,010,992 |
| Family Households | 418 | 9,662 | 80,755,759 |
| Married couple, w/children | 30.1% | 34.6% | 30.5% |
| Married couple, no children | 35.6% | 38.1% | 42.9% |
| Non Family Households | 386 | 3,690 | 43,255,233 |
| Single householder, w/children | 16.7% | 15.9% | 15.8% |
| Single householder, no children | 17.5% | 11.4% | 10.8% |