| | Siletz, OR | Philomath, OR | United States |
| Population | 968 | 5,353 | 329,725,481 |
| Female Population | 52.5% | 48.0% | 50.5% |
| Male Population | 47.5% | 52.0% | 49.5% |
| Median Age | 41.5 | 33.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,210 | 4,602 | 309,327,143 |
| Population - 2000 | 1,133 | 3,838 | 285,036,114 |
| Population - 1990 | 926 | 2,983 | 251,960,433 |
| Pop. 2000 to Now | 15.4% | 46.5% | 15.6% |
| Pop. 1990 to Now | 41.1% | 88.5% | 30.8% |
| space4 | | | |
| Population Density | 1,534.1 | 2,770.7 | 93.4 |
| Land Area | 0.6 | 1.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Siletz, OR | Philomath, OR | United States |
| Age 0 to 4 | 5.0% | 5.7% | 5.9% |
| Age 5 to 9 | 1.2% | 6.7% | 6.1% |
| Age 10 to 14 | 4.4% | 8.2% | 6.6% |
| Age 15 to 17 | 7.4% | 4.1% | 3.9% |
| Age 18 to 20 | 3.6% | 2.4% | 4.0% |
| Age 21 to 24 | 7.4% | 8.9% | 5.2% |
| Age 25 to 34 | 10.6% | 16.4% | 13.8% |
| Age 35 to 44 | 14.1% | 11.4% | 12.9% |
| Age 45 to 54 | 8.7% | 12.5% | 12.6% |
| Age 55 to 59 | 6.6% | 5.7% | 6.7% |
| Age 60 to 64 | 7.1% | 5.2% | 6.3% |
| Age 65 to 74 | 19.3% | 10.3% | 9.6% |
| Age 75 to 84 | 4.0% | 2.2% | 4.5% |
| Age 85 and over | 0.4% | 0.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Siletz, OR | Philomath, OR | United States |
| White | 77.6% | 81.1% | 59.4% |
| Black | 0.9% | 3.6% | 12.2% |
| Asian | 0.0% | 2.2% | 5.6% |
| Native American | 5.6% | 0.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.4% | 0.9% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 9.5% | 3.8% | 3.2% |
| Hispanic | 6.0% | 7.9% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Siletz, OR | Philomath, OR | United States |
| Married Population | 45.3% | 55.6% | 49.8% |
| Currently Married | 43.1% | 53.7% | 48.0% |
| Married but Separated | 2.2% | 1.9% | 1.8% |
| Single Population | 54.7% | 44.4% | 50.2% |
| Never Married | 32.3% | 32.3% | 33.8% |
| Divorced | 17.9% | 9.3% | 10.8% |
| Widowed | 4.5% | 2.8% | 5.6% |
| space5 | | | |
| Household Size | 2.61 | 2.62 | 2.60 |
| Households | 371 | 2,040 | 124,010,992 |
| Family Households | 216 | 1,356 | 80,755,759 |
| Married couple, w/children | 32.4% | 31.9% | 30.5% |
| Married couple, no children | 51.4% | 48.7% | 42.9% |
| Non Family Households | 155 | 684 | 43,255,233 |
| Single householder, w/children | 13.9% | 10.9% | 15.8% |
| Single householder, no children | 2.3% | 8.5% | 10.8% |