| | Pollock, SD | Eureka, SD | United States |
| Population | 210 | 895 | 329,725,481 |
| Female Population | 39.1% | 55.9% | 50.5% |
| Male Population | 61.0% | 44.1% | 49.5% |
| Median Age | 55.3 | 58.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 241 | 864 | 309,327,143 |
| Population - 2000 | 339 | 1,101 | 285,036,114 |
| Population - 1990 | 379 | 1,197 | 251,960,433 |
| Pop. 2000 to Now | -33.0% | -25.8% | 15.6% |
| Pop. 1990 to Now | -40.1% | -31.8% | 30.8% |
| space4 | | | |
| Population Density | 654.2 | 959.3 | 93.4 |
| Land Area | 0.3 | 0.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Pollock, SD | Eureka, SD | United States |
| Age 0 to 4 | 2.9% | 2.6% | 5.9% |
| Age 5 to 9 | 4.3% | 8.6% | 6.1% |
| Age 10 to 14 | 7.6% | 2.8% | 6.6% |
| Age 15 to 17 | 1.9% | 2.3% | 3.9% |
| Age 18 to 20 | 1.4% | 4.5% | 4.0% |
| Age 21 to 24 | 1.9% | 5.6% | 5.2% |
| Age 25 to 34 | 4.3% | 10.8% | 13.8% |
| Age 35 to 44 | 11.0% | 5.0% | 12.9% |
| Age 45 to 54 | 14.3% | 6.4% | 12.6% |
| Age 55 to 59 | 12.9% | 8.5% | 6.7% |
| Age 60 to 64 | 7.1% | 4.0% | 6.3% |
| Age 65 to 74 | 21.4% | 12.7% | 9.6% |
| Age 75 to 84 | 5.2% | 14.4% | 4.5% |
| Age 85 and over | 3.8% | 11.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Pollock, SD | Eureka, SD | United States |
| White | 90.0% | 92.6% | 59.4% |
| Black | 0.0% | 3.4% | 12.2% |
| Asian | 0.0% | 0.7% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 3.3% | 2.8% | 3.2% |
| Hispanic | 6.7% | 0.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Pollock, SD | Eureka, SD | United States |
| Married Population | 67.6% | 47.5% | 49.8% |
| Currently Married | 62.6% | 46.6% | 48.0% |
| Married but Separated | 5.0% | 0.9% | 1.8% |
| Single Population | 32.4% | 52.5% | 50.2% |
| Never Married | 16.8% | 29.9% | 33.8% |
| Divorced | 7.8% | 10.4% | 10.8% |
| Widowed | 7.8% | 12.2% | 5.6% |
| space5 | | | |
| Household Size | 1.86 | 2.09 | 2.60 |
| Households | 113 | 387 | 124,010,992 |
| Family Households | 62 | 176 | 80,755,759 |
| Married couple, w/children | 21.0% | 18.2% | 30.5% |
| Married couple, no children | 69.4% | 63.1% | 42.9% |
| Non Family Households | 51 | 211 | 43,255,233 |
| Single householder, w/children | 9.7% | 14.8% | 15.8% |
| Single householder, no children | 0.0% | 4.0% | 10.8% |