| | Marengo, OH | Malta, MT | United States |
| Population | 280 | 2,031 | 329,725,481 |
| Female Population | 50.4% | 46.0% | 50.5% |
| Male Population | 49.6% | 54.0% | 49.5% |
| Median Age | 45.7 | 49.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 342 | 1,992 | 309,327,143 |
| Population - 2000 | 297 | 2,120 | 285,036,114 |
| Population - 1990 | 393 | 2,340 | 251,960,433 |
| Pop. 2000 to Now | 14.8% | -13.1% | 15.6% |
| Pop. 1990 to Now | -13.2% | -21.2% | 30.8% |
| space4 | | | |
| Population Density | 1,666.7 | 1,973.8 | 93.4 |
| Land Area | 0.2 | 1.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Marengo, OH | Malta, MT | United States |
| Age 0 to 4 | 5.7% | 7.0% | 5.9% |
| Age 5 to 9 | 2.9% | 7.8% | 6.1% |
| Age 10 to 14 | 3.6% | 6.8% | 6.6% |
| Age 15 to 17 | 5.0% | 4.0% | 3.9% |
| Age 18 to 20 | 8.9% | 0.6% | 4.0% |
| Age 21 to 24 | 6.8% | 0.0% | 5.2% |
| Age 25 to 34 | 6.4% | 7.3% | 13.8% |
| Age 35 to 44 | 10.0% | 15.6% | 12.9% |
| Age 45 to 54 | 22.5% | 5.1% | 12.6% |
| Age 55 to 59 | 1.4% | 8.0% | 6.7% |
| Age 60 to 64 | 13.2% | 10.5% | 6.3% |
| Age 65 to 74 | 6.4% | 17.9% | 9.6% |
| Age 75 to 84 | 7.1% | 7.8% | 4.5% |
| Age 85 and over | 0.0% | 1.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Marengo, OH | Malta, MT | United States |
| White | 94.3% | 79.7% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 0.0% | 1.1% | 5.6% |
| Native American | 0.0% | 5.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 5.0% | 7.7% | 3.2% |
| Hispanic | 0.7% | 6.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Marengo, OH | Malta, MT | United States |
| Married Population | 48.8% | 53.4% | 49.8% |
| Currently Married | 47.6% | 53.4% | 48.0% |
| Married but Separated | 1.2% | 0.0% | 1.8% |
| Single Population | 51.2% | 46.6% | 50.2% |
| Never Married | 32.9% | 23.7% | 33.8% |
| Divorced | 8.5% | 8.7% | 10.8% |
| Widowed | 9.8% | 14.2% | 5.6% |
| space5 | | | |
| Household Size | 2.12 | 2.32 | 2.60 |
| Households | 132 | 855 | 124,010,992 |
| Family Households | 87 | 545 | 80,755,759 |
| Married couple, w/children | 31.0% | 31.7% | 30.5% |
| Married couple, no children | 39.1% | 44.2% | 42.9% |
| Non Family Households | 45 | 310 | 43,255,233 |
| Single householder, w/children | 13.8% | 11.9% | 15.8% |
| Single householder, no children | 16.1% | 12.1% | 10.8% |