| | Sebec, ME | Brookfield, NH | United States |
| Population | 521 | 614 | 329,725,481 |
| Female Population | 52.8% | 50.0% | 50.5% |
| Male Population | 47.2% | 50.0% | 49.5% |
| Median Age | 50 | 49.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 630 | 695 | 309,327,143 |
| Population - 2000 | 612 | 604 | 285,036,114 |
| Population - 1990 | 554 | 518 | 251,960,433 |
| Pop. 2000 to Now | -2.5% | 13.9% | 15.6% |
| Pop. 1990 to Now | 7.8% | 32.8% | 30.8% |
| space4 | | | |
| Population Density | 14.2 | 26.9 | 93.4 |
| Land Area | 36.8 | 22.8 | 3,531,905.4 |
| Water Area | 1.1 | 0.4 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Sebec, ME | Brookfield, NH | United States |
| Age 0 to 4 | 7.3% | 1.5% | 5.9% |
| Age 5 to 9 | 4.2% | 3.4% | 6.1% |
| Age 10 to 14 | 4.2% | 3.1% | 6.6% |
| Age 15 to 17 | 6.1% | 1.8% | 3.9% |
| Age 18 to 20 | 1.2% | 5.0% | 4.0% |
| Age 21 to 24 | 1.7% | 7.0% | 5.2% |
| Age 25 to 34 | 10.6% | 6.8% | 13.8% |
| Age 35 to 44 | 8.1% | 7.7% | 12.9% |
| Age 45 to 54 | 16.3% | 24.6% | 12.6% |
| Age 55 to 59 | 10.4% | 8.0% | 6.7% |
| Age 60 to 64 | 11.9% | 8.8% | 6.3% |
| Age 65 to 74 | 11.1% | 16.3% | 9.6% |
| Age 75 to 84 | 4.8% | 3.6% | 4.5% |
| Age 85 and over | 2.1% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Sebec, ME | Brookfield, NH | United States |
| White | 91.4% | 98.2% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 2.3% | 0.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 3.6% | 0.2% | 3.2% |
| Hispanic | 2.7% | 1.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Sebec, ME | Brookfield, NH | United States |
| Married Population | 61.5% | 64.1% | 49.8% |
| Currently Married | 61.0% | 63.7% | 48.0% |
| Married but Separated | 0.5% | 0.4% | 1.8% |
| Single Population | 38.5% | 35.9% | 50.2% |
| Never Married | 23.7% | 22.5% | 33.8% |
| Divorced | 9.8% | 4.4% | 10.8% |
| Widowed | 5.0% | 9.0% | 5.6% |
| space5 | | | |
| Household Size | 2.27 | 2.47 | 2.60 |
| Households | 230 | 249 | 124,010,992 |
| Family Households | 162 | 171 | 80,755,759 |
| Married couple, w/children | 25.3% | 22.2% | 30.5% |
| Married couple, no children | 59.9% | 71.9% | 42.9% |
| Non Family Households | 68 | 78 | 43,255,233 |
| Single householder, w/children | 8.0% | 1.2% | 15.8% |
| Single householder, no children | 6.8% | 4.7% | 10.8% |