| | Astoria, SD | Elkton, SD | United States |
| Population | 153 | 911 | 329,725,481 |
| Female Population | 42.5% | 53.7% | 50.5% |
| Male Population | 57.5% | 46.3% | 49.5% |
| Median Age | 29.8 | 26.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 138 | 732 | 309,327,143 |
| Population - 2000 | 150 | 677 | 285,036,114 |
| Population - 1990 | 155 | 602 | 251,960,433 |
| Pop. 2000 to Now | -10.7% | 7.7% | 15.6% |
| Pop. 1990 to Now | -13.6% | 21.1% | 30.8% |
| space4 | | | |
| Population Density | 974.5 | 609.8 | 93.4 |
| Land Area | 0.2 | 1.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Astoria, SD | Elkton, SD | United States |
| Age 0 to 4 | 10.5% | 15.1% | 5.9% |
| Age 5 to 9 | 8.5% | 14.6% | 6.1% |
| Age 10 to 14 | 9.2% | 8.9% | 6.6% |
| Age 15 to 17 | 6.5% | 5.0% | 3.9% |
| Age 18 to 20 | 0.0% | 3.8% | 4.0% |
| Age 21 to 24 | 6.5% | 1.3% | 5.2% |
| Age 25 to 34 | 15.7% | 14.7% | 13.8% |
| Age 35 to 44 | 16.3% | 11.0% | 12.9% |
| Age 45 to 54 | 5.9% | 8.2% | 12.6% |
| Age 55 to 59 | 3.9% | 3.0% | 6.7% |
| Age 60 to 64 | 2.6% | 5.8% | 6.3% |
| Age 65 to 74 | 9.2% | 6.8% | 9.6% |
| Age 75 to 84 | 3.9% | 1.4% | 4.5% |
| Age 85 and over | 1.3% | 0.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Astoria, SD | Elkton, SD | United States |
| White | 95.4% | 64.4% | 59.4% |
| Black | 0.0% | 0.2% | 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 | 0.0% | 4.9% | 3.2% |
| Hispanic | 4.6% | 30.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Astoria, SD | Elkton, SD | United States |
| Married Population | 67.3% | 58.5% | 49.8% |
| Currently Married | 67.3% | 55.6% | 48.0% |
| Married but Separated | 0.0% | 2.9% | 1.8% |
| Single Population | 32.7% | 41.5% | 50.2% |
| Never Married | 19.1% | 28.8% | 33.8% |
| Divorced | 10.0% | 7.7% | 10.8% |
| Widowed | 3.6% | 5.0% | 5.6% |
| space5 | | | |
| Household Size | 2.43 | 3.20 | 2.60 |
| Households | 63 | 285 | 124,010,992 |
| Family Households | 46 | 200 | 80,755,759 |
| Married couple, w/children | 43.5% | 39.0% | 30.5% |
| Married couple, no children | 43.5% | 33.5% | 42.9% |
| Non Family Households | 17 | 85 | 43,255,233 |
| Single householder, w/children | 10.9% | 21.0% | 15.8% |
| Single householder, no children | 2.2% | 6.5% | 10.8% |