| | De Smet, SD | Hot Springs, SD | United States |
| Population | 1,128 | 3,407 | 329,725,481 |
| Female Population | 48.0% | 45.4% | 50.5% |
| Male Population | 52.0% | 54.6% | 49.5% |
| Median Age | 45.3 | 54.9 | 38.4 |
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| Population - 2010 | 1,087 | 3,740 | 309,327,143 |
| Population - 2000 | 1,164 | 4,129 | 285,036,114 |
| Population - 1990 | 1,172 | 4,325 | 251,960,433 |
| Pop. 2000 to Now | -9.2% | -15.2% | 15.6% |
| Pop. 1990 to Now | -9.8% | -19.0% | 30.8% |
| space4 | | | |
| Population Density | 974.1 | 962.4 | 93.4 |
| Land Area | 1.2 | 3.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | De Smet, SD | Hot Springs, SD | United States |
| Age 0 to 4 | 4.1% | 3.3% | 5.9% |
| Age 5 to 9 | 7.4% | 5.6% | 6.1% |
| Age 10 to 14 | 7.9% | 4.8% | 6.6% |
| Age 15 to 17 | 4.1% | 2.7% | 3.9% |
| Age 18 to 20 | 2.1% | 3.0% | 4.0% |
| Age 21 to 24 | 2.7% | 2.8% | 5.2% |
| Age 25 to 34 | 7.4% | 10.7% | 13.8% |
| Age 35 to 44 | 14.0% | 7.7% | 12.9% |
| Age 45 to 54 | 8.8% | 9.7% | 12.6% |
| Age 55 to 59 | 4.5% | 9.0% | 6.7% |
| Age 60 to 64 | 7.1% | 9.6% | 6.3% |
| Age 65 to 74 | 12.6% | 16.6% | 9.6% |
| Age 75 to 84 | 8.2% | 9.4% | 4.5% |
| Age 85 and over | 9.3% | 5.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | De Smet, SD | Hot Springs, SD | United States |
| White | 98.2% | 75.3% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 0.0% | 1.9% | 5.6% |
| Native American | 0.7% | 13.7% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.1% | 8.4% | 3.2% |
| Hispanic | 0.0% | 0.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | De Smet, SD | Hot Springs, SD | United States |
| Married Population | 56.5% | 36.4% | 49.8% |
| Currently Married | 55.9% | 33.6% | 48.0% |
| Married but Separated | 0.5% | 2.9% | 1.8% |
| Single Population | 43.5% | 63.6% | 50.2% |
| Never Married | 21.5% | 24.4% | 33.8% |
| Divorced | 12.1% | 27.4% | 10.8% |
| Widowed | 9.9% | 11.7% | 5.6% |
| space5 | | | |
| Household Size | 2.53 | 1.96 | 2.60 |
| Households | 429 | 1,630 | 124,010,992 |
| Family Households | 271 | 861 | 80,755,759 |
| Married couple, w/children | 34.3% | 9.1% | 30.5% |
| Married couple, no children | 48.7% | 41.5% | 42.9% |
| Non Family Households | 158 | 769 | 43,255,233 |
| Single householder, w/children | 7.7% | 17.1% | 15.8% |
| Single householder, no children | 9.2% | 32.4% | 10.8% |