| Underhill - Population Characteristics | FIPS Code=07075 |
| 1970 | 1980 | 1990 | |
| Population Density (Persons per Square Mile) | 0.17 | 0.31 | 54.90 |
| Total Population | 1198 | 2172 | 2799 |
| Per Cent of Popualtion Born within Vermont | 65.00 | 52.59 | 52.70 |
| Number of Families | 252 | 550 | 766 |
| Per Cent of Population Aged 18 or Younger | 44.40 | 35.50 | 32.33 |
| Per Cent of Population Aged 18 to 64 | 47.91 | 58.65 | 62.77 |
| Per Cent of Population Aged 65 or Older | 7.69 | 5.85 | 4.89 |