| | Monmouth, ME | Lisbon, ME | United States |
| Population | 4,061 | 9,588 | 329,725,481 |
| Female Population | 45.6% | 50.8% | 50.5% |
| Male Population | 54.5% | 49.2% | 49.5% |
| Median Age | 46.6 | 36.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 4,109 | 9,017 | 309,327,143 |
| Population - 2000 | 3,785 | 9,077 | 285,036,114 |
| Population - 1990 | 3,353 | 9,457 | 251,960,433 |
| Pop. 2000 to Now | 10.2% | -0.3% | 15.6% |
| Pop. 1990 to Now | 24.4% | -4.3% | 30.8% |
| space4 | | | |
| Population Density | 119.3 | 420.1 | 93.4 |
| Land Area | 34.0 | 22.8 | 3,531,905.4 |
| Water Area | 5.0 | 1.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Monmouth, ME | Lisbon, ME | United States |
| Age 0 to 4 | 4.0% | 7.9% | 5.9% |
| Age 5 to 9 | 6.2% | 8.3% | 6.1% |
| Age 10 to 14 | 4.5% | 8.0% | 6.6% |
| Age 15 to 17 | 5.7% | 2.7% | 3.9% |
| Age 18 to 20 | 2.8% | 3.3% | 4.0% |
| Age 21 to 24 | 3.2% | 3.0% | 5.2% |
| Age 25 to 34 | 5.7% | 12.3% | 13.8% |
| Age 35 to 44 | 14.4% | 16.8% | 12.9% |
| Age 45 to 54 | 19.3% | 12.9% | 12.6% |
| Age 55 to 59 | 12.4% | 7.1% | 6.7% |
| Age 60 to 64 | 6.4% | 6.2% | 6.3% |
| Age 65 to 74 | 11.9% | 6.5% | 9.6% |
| Age 75 to 84 | 2.5% | 4.3% | 4.5% |
| Age 85 and over | 0.9% | 0.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Monmouth, ME | Lisbon, ME | United States |
| White | 95.5% | 93.8% | 59.4% |
| Black | 0.2% | 0.1% | 12.2% |
| Asian | 0.4% | 0.2% | 5.6% |
| Native American | 0.3% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.2% | 4.1% | 3.2% |
| Hispanic | 1.3% | 1.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Monmouth, ME | Lisbon, ME | United States |
| Married Population | 53.1% | 57.9% | 49.8% |
| Currently Married | 53.1% | 57.0% | 48.0% |
| Married but Separated | 0.0% | 0.9% | 1.8% |
| Single Population | 46.9% | 42.1% | 50.2% |
| Never Married | 23.0% | 24.7% | 33.8% |
| Divorced | 20.1% | 13.6% | 10.8% |
| Widowed | 3.8% | 3.7% | 5.6% |
| space5 | | | |
| Household Size | 2.33 | 2.55 | 2.60 |
| Households | 1,740 | 3,710 | 124,010,992 |
| Family Households | 1,118 | 2,554 | 80,755,759 |
| Married couple, w/children | 27.5% | 34.0% | 30.5% |
| Married couple, no children | 51.7% | 45.5% | 42.9% |
| Non Family Households | 622 | 1,156 | 43,255,233 |
| Single householder, w/children | 14.0% | 13.9% | 15.8% |
| Single householder, no children | 6.8% | 6.6% | 10.8% |