| | Petersburg, AK | Brookings, OR | United States |
| Population | 3,259 | 6,706 | 329,725,481 |
| Female Population | 48.2% | 48.9% | 50.5% |
| Male Population | 51.8% | 51.2% | 49.5% |
| Median Age | 48.2 | 54.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,934 | 6,343 | 309,327,143 |
| Population - 2000 | 3,224 | 5,447 | 285,036,114 |
| Population - 1990 | 3,207 | 4,400 | 251,960,433 |
| Pop. 2000 to Now | -2.9% | 20.5% | 15.6% |
| Pop. 1990 to Now | -2.4% | 49.1% | 30.8% |
| space4 | | | |
| Population Density | 73.8 | 1,617.5 | 93.4 |
| Land Area | 44.2 | 4.1 | 3,531,905.4 |
| Water Area | 2.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Petersburg, AK | Brookings, OR | United States |
| Age 0 to 4 | 5.5% | 4.3% | 5.9% |
| Age 5 to 9 | 5.1% | 3.5% | 6.1% |
| Age 10 to 14 | 5.2% | 1.6% | 6.6% |
| Age 15 to 17 | 2.7% | 2.8% | 3.9% |
| Age 18 to 20 | 3.9% | 1.3% | 4.0% |
| Age 21 to 24 | 2.6% | 3.9% | 5.2% |
| Age 25 to 34 | 12.2% | 16.0% | 13.8% |
| Age 35 to 44 | 10.0% | 6.8% | 12.9% |
| Age 45 to 54 | 9.2% | 10.6% | 12.6% |
| Age 55 to 59 | 9.5% | 9.1% | 6.7% |
| Age 60 to 64 | 6.5% | 13.2% | 6.3% |
| Age 65 to 74 | 16.0% | 15.1% | 9.6% |
| Age 75 to 84 | 10.5% | 6.2% | 4.5% |
| Age 85 and over | 1.2% | 5.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Petersburg, AK | Brookings, OR | United States |
| White | 60.0% | 83.8% | 59.4% |
| Black | 1.0% | 0.3% | 12.2% |
| Asian | 16.8% | 1.6% | 5.6% |
| Native American | 5.9% | 1.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 0.0% | 0.2% |
| Other | 0.2% | 0.0% | 0.4% |
| Two or More Races | 10.0% | 4.7% | 3.2% |
| Hispanic | 5.9% | 8.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Petersburg, AK | Brookings, OR | United States |
| Married Population | 57.1% | 57.7% | 49.8% |
| Currently Married | 56.7% | 57.2% | 48.0% |
| Married but Separated | 0.4% | 0.5% | 1.8% |
| Single Population | 42.9% | 42.3% | 50.2% |
| Never Married | 28.0% | 20.6% | 33.8% |
| Divorced | 8.2% | 17.1% | 10.8% |
| Widowed | 6.6% | 4.6% | 5.6% |
| space5 | | | |
| Household Size | 2.77 | 2.11 | 2.60 |
| Households | 1,162 | 3,112 | 124,010,992 |
| Family Households | 746 | 2,122 | 80,755,759 |
| Married couple, w/children | 25.9% | 18.5% | 30.5% |
| Married couple, no children | 57.9% | 59.3% | 42.9% |
| Non Family Households | 416 | 990 | 43,255,233 |
| Single householder, w/children | 9.7% | 13.1% | 15.8% |
| Single householder, no children | 6.6% | 9.0% | 10.8% |