| | Mandan, ND | Bismarck, ND | United States |
| Population | 23,784 | 73,321 | 329,725,481 |
| Female Population | 49.4% | 50.7% | 50.5% |
| Male Population | 50.6% | 49.4% | 49.5% |
| Median Age | 35.5 | 37.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 18,948 | 61,595 | 309,327,143 |
| Population - 2000 | 16,718 | 55,532 | 285,036,114 |
| Population - 1990 | 15,177 | 49,256 | 251,960,433 |
| Pop. 2000 to Now | 36.7% | 33.3% | 15.6% |
| Pop. 1990 to Now | 50.6% | 50.3% | 30.8% |
| space4 | | | |
| Population Density | 1,761.4 | 2,173.3 | 93.4 |
| Land Area | 13.5 | 33.7 | 3,531,905.4 |
| Water Area | 0.1 | 0.5 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Mandan, ND | Bismarck, ND | United States |
| Age 0 to 4 | 5.9% | 6.4% | 5.9% |
| Age 5 to 9 | 6.3% | 6.2% | 6.1% |
| Age 10 to 14 | 6.7% | 6.2% | 6.6% |
| Age 15 to 17 | 3.8% | 3.5% | 3.9% |
| Age 18 to 20 | 4.0% | 4.1% | 4.0% |
| Age 21 to 24 | 5.7% | 5.0% | 5.2% |
| Age 25 to 34 | 16.4% | 14.6% | 13.8% |
| Age 35 to 44 | 12.6% | 13.4% | 12.9% |
| Age 45 to 54 | 12.1% | 10.8% | 12.6% |
| Age 55 to 59 | 6.1% | 5.9% | 6.7% |
| Age 60 to 64 | 5.6% | 6.7% | 6.3% |
| Age 65 to 74 | 9.6% | 9.3% | 9.6% |
| Age 75 to 84 | 3.6% | 5.2% | 4.5% |
| Age 85 and over | 1.6% | 2.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Mandan, ND | Bismarck, ND | United States |
| White | 85.5% | 85.7% | 59.4% |
| Black | 1.6% | 2.6% | 12.2% |
| Asian | 1.2% | 0.8% | 5.6% |
| Native American | 4.5% | 4.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.3% | 0.2% |
| Other | 0.3% | 0.1% | 0.4% |
| Two or More Races | 2.1% | 3.7% | 3.2% |
| Hispanic | 4.8% | 2.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Mandan, ND | Bismarck, ND | United States |
| Married Population | 55.2% | 49.4% | 49.8% |
| Currently Married | 54.6% | 48.5% | 48.0% |
| Married but Separated | 0.5% | 0.9% | 1.8% |
| Single Population | 44.8% | 50.6% | 50.2% |
| Never Married | 30.4% | 33.1% | 33.8% |
| Divorced | 9.5% | 11.4% | 10.8% |
| Widowed | 4.9% | 6.1% | 5.6% |
| space5 | | | |
| Household Size | 2.41 | 2.28 | 2.60 |
| Households | 9,697 | 31,227 | 124,010,992 |
| Family Households | 6,423 | 17,997 | 80,755,759 |
| Married couple, w/children | 31.2% | 31.9% | 30.5% |
| Married couple, no children | 48.3% | 45.2% | 42.9% |
| Non Family Households | 3,274 | 13,230 | 43,255,233 |
| Single householder, w/children | 14.2% | 16.6% | 15.8% |
| Single householder, no children | 6.3% | 6.4% | 10.8% |