| | Portal, ND | Plentywood, MT | United States |
| Population | 117 | 1,660 | 329,725,481 |
| Female Population | 51.3% | 50.6% | 50.5% |
| Male Population | 48.7% | 49.4% | 49.5% |
| Median Age | 47.1 | 49.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 126 | 1,739 | 309,327,143 |
| Population - 2000 | 131 | 2,061 | 285,036,114 |
| Population - 1990 | 192 | 2,136 | 251,960,433 |
| Pop. 2000 to Now | 9.2% | -16.9% | 15.6% |
| Pop. 1990 to Now | -25.5% | -19.9% | 30.8% |
| space4 | | | |
| Population Density | 174.6 | 1,223.3 | 93.4 |
| Land Area | 0.7 | 1.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Portal, ND | Plentywood, MT | United States |
| Age 0 to 4 | 12.8% | 5.3% | 5.9% |
| Age 5 to 9 | 1.7% | 5.6% | 6.1% |
| Age 10 to 14 | 0.9% | 5.2% | 6.6% |
| Age 15 to 17 | 0.0% | 1.6% | 3.9% |
| Age 18 to 20 | 1.7% | 5.7% | 4.0% |
| Age 21 to 24 | 0.0% | 2.7% | 5.2% |
| Age 25 to 34 | 29.1% | 10.5% | 13.8% |
| Age 35 to 44 | 1.7% | 8.9% | 12.9% |
| Age 45 to 54 | 26.5% | 8.6% | 12.6% |
| Age 55 to 59 | 2.6% | 9.2% | 6.7% |
| Age 60 to 64 | 7.7% | 12.8% | 6.3% |
| Age 65 to 74 | 9.4% | 12.3% | 9.6% |
| Age 75 to 84 | 5.1% | 5.5% | 4.5% |
| Age 85 and over | 0.9% | 6.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Portal, ND | Plentywood, MT | United States |
| White | 77.8% | 87.8% | 59.4% |
| Black | 12.0% | 0.0% | 12.2% |
| Asian | 0.0% | 1.1% | 5.6% |
| Native American | 6.8% | 2.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.0% | 4.6% | 3.2% |
| Hispanic | 3.4% | 4.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Portal, ND | Plentywood, MT | United States |
| Married Population | 64.6% | 47.0% | 49.8% |
| Currently Married | 64.6% | 47.0% | 48.0% |
| Married but Separated | 0.0% | 0.0% | 1.8% |
| Single Population | 35.4% | 53.0% | 50.2% |
| Never Married | 23.2% | 28.3% | 33.8% |
| Divorced | 8.1% | 16.6% | 10.8% |
| Widowed | 4.0% | 8.1% | 5.6% |
| space5 | | | |
| Household Size | 1.70 | 2.15 | 2.60 |
| Households | 69 | 742 | 124,010,992 |
| Family Households | 39 | 403 | 80,755,759 |
| Married couple, w/children | 23.1% | 25.6% | 30.5% |
| Married couple, no children | 61.5% | 56.3% | 42.9% |
| Non Family Households | 30 | 339 | 43,255,233 |
| Single householder, w/children | 7.7% | 11.9% | 15.8% |
| Single householder, no children | 7.7% | 6.2% | 10.8% |