| | Thetford, VT | Lyme, NH | United States |
| Population | 2,765 | 1,658 | 329,725,481 |
| Female Population | 50.3% | 51.8% | 50.5% |
| Male Population | 49.7% | 48.3% | 49.5% |
| Median Age | 47.2 | 47.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,587 | 1,714 | 309,327,143 |
| Population - 2000 | 2,617 | 1,679 | 285,036,114 |
| Population - 1990 | 2,438 | 1,496 | 251,960,433 |
| Pop. 2000 to Now | -3.5% | 0.4% | 15.6% |
| Pop. 1990 to Now | 3.6% | 12.6% | 30.8% |
| space4 | | | |
| Population Density | 63.7 | 30.8 | 93.4 |
| Land Area | 43.4 | 53.8 | 3,531,905.4 |
| Water Area | 1.0 | 0.9 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Thetford, VT | Lyme, NH | United States |
| Age 0 to 4 | 3.3% | 5.1% | 5.9% |
| Age 5 to 9 | 3.8% | 3.3% | 6.1% |
| Age 10 to 14 | 5.8% | 7.6% | 6.6% |
| Age 15 to 17 | 3.8% | 4.2% | 3.9% |
| Age 18 to 20 | 4.4% | 4.5% | 4.0% |
| Age 21 to 24 | 5.9% | 2.8% | 5.2% |
| Age 25 to 34 | 12.5% | 9.2% | 13.8% |
| Age 35 to 44 | 7.5% | 11.0% | 12.9% |
| Age 45 to 54 | 15.6% | 12.4% | 12.6% |
| Age 55 to 59 | 7.4% | 5.7% | 6.7% |
| Age 60 to 64 | 12.6% | 9.5% | 6.3% |
| Age 65 to 74 | 12.9% | 17.9% | 9.6% |
| Age 75 to 84 | 2.6% | 4.5% | 4.5% |
| Age 85 and over | 1.9% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Thetford, VT | Lyme, NH | United States |
| White | 91.5% | 92.3% | 59.4% |
| Black | 0.0% | 0.1% | 12.2% |
| Asian | 1.2% | 2.5% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.4% | 0.0% | 0.4% |
| Two or More Races | 4.4% | 2.4% | 3.2% |
| Hispanic | 2.4% | 2.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Thetford, VT | Lyme, NH | United States |
| Married Population | 50.6% | 59.3% | 49.8% |
| Currently Married | 50.3% | 58.9% | 48.0% |
| Married but Separated | 0.3% | 0.4% | 1.8% |
| Single Population | 49.4% | 40.7% | 50.2% |
| Never Married | 28.7% | 25.2% | 33.8% |
| Divorced | 18.3% | 11.2% | 10.8% |
| Widowed | 2.5% | 4.3% | 5.6% |
| space5 | | | |
| Household Size | 2.31 | 2.70 | 2.60 |
| Households | 1,198 | 609 | 124,010,992 |
| Family Households | 781 | 444 | 80,755,759 |
| Married couple, w/children | 23.6% | 33.6% | 30.5% |
| Married couple, no children | 50.6% | 55.6% | 42.9% |
| Non Family Households | 417 | 165 | 43,255,233 |
| Single householder, w/children | 6.5% | 6.3% | 15.8% |
| Single householder, no children | 19.3% | 4.5% | 10.8% |