| | South Glastonbury, MT | United States, MT |
| Population | 393 | 329,725,481 |
| Female Population | 47.6% | 50.5% |
| Male Population | 52.4% | 49.5% |
| Median Age | 58.8 | 38.4 |
| space3 | | |
| Population - 2010 | 284 | 309,327,143 |
| Population - 2000 | 192 | 285,036,114 |
| Population - 1990 | 165 | 251,960,433 |
| Pop. 2000 to Now | 74.0% | 15.6% |
| Pop. 1990 to Now | 102.4% | 30.8% |
| space4 | | |
| Population Density | 22.5 | 93.4 |
| Land Area | 17.5 | 3,531,905.4 |
| Water Area | 0.3 | 264,836.8 |
| space | | |
| Est. Total Population By Age | | |
| | South Glastonbury, MT | South Glastonbury, MT |
| Age 0 to 4 | 2.3% | 5.9% |
| Age 5 to 9 | 2.0% | 6.1% |
| Age 10 to 14 | 2.5% | 6.6% |
| Age 15 to 17 | 2.8% | 3.9% |
| Age 18 to 20 | 0.0% | 4.0% |
| Age 21 to 24 | 0.0% | 5.2% |
| Age 25 to 34 | 9.4% | 13.8% |
| Age 35 to 44 | 1.0% | 12.9% |
| Age 45 to 54 | 13.0% | 12.6% |
| Age 55 to 59 | 31.0% | 6.7% |
| Age 60 to 64 | 9.4% | 6.3% |
| Age 65 to 74 | 10.2% | 9.6% |
| Age 75 to 84 | 16.3% | 4.5% |
| Age 85 and over | 0.0% | 1.9% |
| space1 | | |
| Race | | |
| | South Glastonbury, MT | South Glastonbury, MT |
| White | 93.4% | 59.4% |
| Black | 0.0% | 12.2% |
| Asian | 2.3% | 5.6% |
| Native American | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% |
| Other | 0.0% | 0.4% |
| Two or More Races | 4.3% | 3.2% |
| Hispanic | 0.0% | 18.4% |
| space2 | | |
| Marriage & Family | | |
| | South Glastonbury, MT | South Glastonbury, MT |
| Married Population | 82.8% | 49.8% |
| Currently Married | 82.8% | 48.0% |
| Married but Separated | 0.0% | 1.8% |
| Single Population | 17.2% | 50.2% |
| Never Married | 8.2% | 33.8% |
| Divorced | 9.0% | 10.8% |
| Widowed | 0.0% | 5.6% |
| space5 | | |
| Household Size | 1.77 | 2.60 |
| Households | 222 | 124,010,992 |
| Family Households | 156 | 80,755,759 |
| Married couple, w/children | 9.6% | 30.5% |
| Married couple, no children | 75.0% | 42.9% |
| Non Family Households | 66 | 43,255,233 |
| Single householder, w/children | 2.6% | 15.8% |
| Single householder, no children | 12.8% | 10.8% |