| | Knox, ME | Brewer, ME | United States |
| Population | 807 | 9,606 | 329,725,481 |
| Female Population | 45.7% | 53.3% | 50.5% |
| Male Population | 54.3% | 46.7% | 49.5% |
| Median Age | 36.7 | 39 | 38.4 |
| space3 | | | |
| Population - 2010 | 802 | 9,476 | 309,327,143 |
| Population - 2000 | 747 | 8,987 | 285,036,114 |
| Population - 1990 | 681 | 9,021 | 251,960,433 |
| Pop. 2000 to Now | 5.9% | -0.4% | 15.6% |
| Pop. 1990 to Now | 16.2% | -0.8% | 30.8% |
| space4 | | | |
| Population Density | 27.8 | 630.6 | 93.4 |
| Land Area | 29.0 | 15.2 | 3,531,905.4 |
| Water Area | 0.2 | 0.5 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Knox, ME | Brewer, ME | United States |
| Age 0 to 4 | 2.4% | 5.6% | 5.9% |
| Age 5 to 9 | 7.4% | 6.3% | 6.1% |
| Age 10 to 14 | 4.8% | 5.2% | 6.6% |
| Age 15 to 17 | 2.4% | 4.5% | 3.9% |
| Age 18 to 20 | 3.7% | 1.9% | 4.0% |
| Age 21 to 24 | 3.3% | 4.4% | 5.2% |
| Age 25 to 34 | 22.1% | 16.2% | 13.8% |
| Age 35 to 44 | 13.4% | 12.6% | 12.9% |
| Age 45 to 54 | 12.9% | 13.6% | 12.6% |
| Age 55 to 59 | 8.4% | 7.4% | 6.7% |
| Age 60 to 64 | 6.1% | 5.5% | 6.3% |
| Age 65 to 74 | 8.7% | 9.2% | 9.6% |
| Age 75 to 84 | 2.0% | 5.0% | 4.5% |
| Age 85 and over | 2.5% | 2.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Knox, ME | Brewer, ME | United States |
| White | 97.5% | 95.2% | 59.4% |
| Black | 0.0% | 0.5% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.9% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.2% | 1.0% | 0.4% |
| Two or More Races | 0.4% | 2.5% | 3.2% |
| Hispanic | 0.0% | 0.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Knox, ME | Brewer, ME | United States |
| Married Population | 52.0% | 41.3% | 49.8% |
| Currently Married | 52.0% | 40.4% | 48.0% |
| Married but Separated | 0.0% | 0.9% | 1.8% |
| Single Population | 48.0% | 58.7% | 50.2% |
| Never Married | 31.6% | 32.2% | 33.8% |
| Divorced | 9.4% | 19.6% | 10.8% |
| Widowed | 7.0% | 7.0% | 5.6% |
| space5 | | | |
| Household Size | 2.60 | 2.32 | 2.60 |
| Households | 310 | 4,074 | 124,010,992 |
| Family Households | 213 | 2,110 | 80,755,759 |
| Married couple, w/children | 21.6% | 25.1% | 30.5% |
| Married couple, no children | 57.7% | 43.8% | 42.9% |
| Non Family Households | 97 | 1,964 | 43,255,233 |
| Single householder, w/children | 12.7% | 23.6% | 15.8% |
| Single householder, no children | 8.0% | 7.5% | 10.8% |