| | Houlton, ME | Calais, ME | United States |
| Population | 6,072 | 3,010 | 329,725,481 |
| Female Population | 50.4% | 52.2% | 50.5% |
| Male Population | 49.6% | 47.8% | 49.5% |
| Median Age | 44.3 | 51.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 6,120 | 3,120 | 309,327,143 |
| Population - 2000 | 6,476 | 3,447 | 285,036,114 |
| Population - 1990 | 6,613 | 3,963 | 251,960,433 |
| Pop. 2000 to Now | -11.0% | -12.2% | 15.6% |
| Pop. 1990 to Now | -12.8% | -23.6% | 30.8% |
| space4 | | | |
| Population Density | 165.4 | 87.7 | 93.4 |
| Land Area | 36.7 | 34.3 | 3,531,905.4 |
| Water Area | 0.0 | 5.8 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Houlton, ME | Calais, ME | United States |
| Age 0 to 4 | 3.5% | 6.5% | 5.9% |
| Age 5 to 9 | 5.6% | 1.9% | 6.1% |
| Age 10 to 14 | 7.2% | 1.6% | 6.6% |
| Age 15 to 17 | 4.6% | 4.0% | 3.9% |
| Age 18 to 20 | 5.2% | 3.8% | 4.0% |
| Age 21 to 24 | 5.2% | 3.7% | 5.2% |
| Age 25 to 34 | 8.4% | 7.4% | 13.8% |
| Age 35 to 44 | 11.5% | 9.8% | 12.9% |
| Age 45 to 54 | 14.1% | 14.1% | 12.6% |
| Age 55 to 59 | 5.9% | 6.1% | 6.7% |
| Age 60 to 64 | 6.2% | 12.2% | 6.3% |
| Age 65 to 74 | 11.5% | 13.6% | 9.6% |
| Age 75 to 84 | 6.2% | 11.1% | 4.5% |
| Age 85 and over | 4.8% | 4.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Houlton, ME | Calais, ME | United States |
| White | 89.0% | 96.0% | 59.4% |
| Black | 2.4% | 0.4% | 12.2% |
| Asian | 0.1% | 0.5% | 5.6% |
| Native American | 4.2% | 0.8% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.2% | 1.4% | 3.2% |
| Hispanic | 3.0% | 0.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Houlton, ME | Calais, ME | United States |
| Married Population | 44.5% | 50.7% | 49.8% |
| Currently Married | 43.6% | 49.5% | 48.0% |
| Married but Separated | 0.9% | 1.2% | 1.8% |
| Single Population | 55.5% | 49.3% | 50.2% |
| Never Married | 29.4% | 22.1% | 33.8% |
| Divorced | 13.9% | 16.8% | 10.8% |
| Widowed | 12.3% | 10.5% | 5.6% |
| space5 | | | |
| Household Size | 2.28 | 1.74 | 2.60 |
| Households | 2,514 | 1,664 | 124,010,992 |
| Family Households | 1,336 | 928 | 80,755,759 |
| Married couple, w/children | 33.5% | 16.7% | 30.5% |
| Married couple, no children | 47.1% | 57.0% | 42.9% |
| Non Family Households | 1,178 | 736 | 43,255,233 |
| Single householder, w/children | 11.8% | 21.7% | 15.8% |
| Single householder, no children | 7.6% | 4.6% | 10.8% |