| | Hartville, MO | Sundance, WY | United States |
| Population | 641 | 1,361 | 329,725,481 |
| Female Population | 42.6% | 57.2% | 50.5% |
| Male Population | 57.4% | 42.8% | 49.5% |
| Median Age | 58.4 | 30.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 640 | 1,191 | 309,327,143 |
| Population - 2000 | 607 | 1,161 | 285,036,114 |
| Population - 1990 | 495 | 1,139 | 251,960,433 |
| Pop. 2000 to Now | 1.8% | 11.6% | 15.6% |
| Pop. 1990 to Now | 24.9% | 13.8% | 30.8% |
| space4 | | | |
| Population Density | 983.1 | 446.1 | 93.4 |
| Land Area | 0.7 | 3.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Hartville, MO | Sundance, WY | United States |
| Age 0 to 4 | 3.6% | 12.5% | 5.9% |
| Age 5 to 9 | 2.8% | 5.2% | 6.1% |
| Age 10 to 14 | 3.9% | 3.0% | 6.6% |
| Age 15 to 17 | 1.1% | 1.8% | 3.9% |
| Age 18 to 20 | 3.0% | 3.2% | 4.0% |
| Age 21 to 24 | 5.1% | 4.6% | 5.2% |
| Age 25 to 34 | 9.8% | 28.8% | 13.8% |
| Age 35 to 44 | 7.2% | 5.2% | 12.9% |
| Age 45 to 54 | 11.1% | 6.1% | 12.6% |
| Age 55 to 59 | 4.2% | 6.0% | 6.7% |
| Age 60 to 64 | 23.2% | 6.2% | 6.3% |
| Age 65 to 74 | 14.0% | 10.9% | 9.6% |
| Age 75 to 84 | 8.3% | 4.8% | 4.5% |
| Age 85 and over | 2.7% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Hartville, MO | Sundance, WY | United States |
| White | 90.3% | 88.8% | 59.4% |
| Black | 2.3% | 0.0% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 6.4% | 5.2% | 3.2% |
| Hispanic | 0.9% | 6.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Hartville, MO | Sundance, WY | United States |
| Married Population | 53.2% | 56.2% | 49.8% |
| Currently Married | 40.7% | 56.2% | 48.0% |
| Married but Separated | 12.5% | 0.0% | 1.8% |
| Single Population | 46.8% | 43.8% | 50.2% |
| Never Married | 23.1% | 23.0% | 33.8% |
| Divorced | 15.3% | 15.9% | 10.8% |
| Widowed | 8.3% | 4.9% | 5.6% |
| space5 | | | |
| Household Size | 1.99 | 2.31 | 2.60 |
| Households | 288 | 566 | 124,010,992 |
| Family Households | 134 | 377 | 80,755,759 |
| Married couple, w/children | 6.7% | 42.2% | 30.5% |
| Married couple, no children | 73.9% | 43.0% | 42.9% |
| Non Family Households | 154 | 189 | 43,255,233 |
| Single householder, w/children | 9.7% | 9.3% | 15.8% |
| Single householder, no children | 9.7% | 5.6% | 10.8% |