| | Marion, UT | Mount Pleasant, UT | United States |
| Population | 549 | 3,621 | 329,725,481 |
| Female Population | 41.4% | 49.0% | 50.5% |
| Male Population | 58.7% | 51.0% | 49.5% |
| Median Age | 21.7 | 32.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 367 | 3,266 | 309,327,143 |
| Population - 2000 | 481 | 2,707 | 285,036,114 |
| Population - 1990 | 342 | 2,092 | 251,960,433 |
| Pop. 2000 to Now | 39.1% | 32.3% | 15.6% |
| Pop. 1990 to Now | 95.6% | 71.1% | 30.8% |
| space4 | | | |
| Population Density | 94.4 | 1,235.8 | 93.4 |
| Land Area | 5.8 | 2.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Marion, UT | Mount Pleasant, UT | United States |
| Age 0 to 4 | 4.7% | 5.9% | 5.9% |
| Age 5 to 9 | 10.2% | 6.1% | 6.1% |
| Age 10 to 14 | 7.8% | 9.8% | 6.6% |
| Age 15 to 17 | 8.0% | 7.4% | 3.9% |
| Age 18 to 20 | 7.5% | 5.2% | 4.0% |
| Age 21 to 24 | 18.2% | 6.1% | 5.2% |
| Age 25 to 34 | 4.6% | 12.8% | 13.8% |
| Age 35 to 44 | 4.9% | 12.1% | 12.9% |
| Age 45 to 54 | 13.3% | 9.9% | 12.6% |
| Age 55 to 59 | 11.1% | 4.4% | 6.7% |
| Age 60 to 64 | 1.5% | 4.4% | 6.3% |
| Age 65 to 74 | 5.5% | 10.0% | 9.6% |
| Age 75 to 84 | 2.7% | 5.0% | 4.5% |
| Age 85 and over | 0.0% | 1.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Marion, UT | Mount Pleasant, UT | United States |
| White | 100.0% | 89.7% | 59.4% |
| Black | 0.0% | 1.1% | 12.2% |
| Asian | 0.0% | 1.0% | 5.6% |
| Native American | 0.0% | 0.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 1.1% | 0.2% |
| Other | 0.0% | 0.3% | 0.4% |
| Two or More Races | 0.0% | 2.7% | 3.2% |
| Hispanic | 0.0% | 3.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Marion, UT | Mount Pleasant, UT | United States |
| Married Population | 45.8% | 62.9% | 49.8% |
| Currently Married | 45.8% | 60.4% | 48.0% |
| Married but Separated | 0.0% | 2.5% | 1.8% |
| Single Population | 54.2% | 37.1% | 50.2% |
| Never Married | 46.2% | 27.8% | 33.8% |
| Divorced | 4.5% | 5.5% | 10.8% |
| Widowed | 3.5% | 3.8% | 5.6% |
| space5 | | | |
| Household Size | 4.26 | 2.90 | 2.60 |
| Households | 129 | 1,145 | 124,010,992 |
| Family Households | 95 | 879 | 80,755,759 |
| Married couple, w/children | 53.7% | 44.3% | 30.5% |
| Married couple, no children | 46.3% | 42.1% | 42.9% |
| Non Family Households | 34 | 266 | 43,255,233 |
| Single householder, w/children | 0.0% | 8.3% | 15.8% |
| Single householder, no children | 0.0% | 5.3% | 10.8% |