| | Yankton, SD | Fordyce, NE | United States |
| Population | 15,332 | 207 | 329,725,481 |
| Female Population | 48.7% | 46.4% | 50.5% |
| Male Population | 51.3% | 53.6% | 49.5% |
| Median Age | 40.4 | 34.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 14,470 | 138 | 309,327,143 |
| Population - 2000 | 13,528 | 182 | 285,036,114 |
| Population - 1990 | 12,703 | 190 | 251,960,433 |
| Pop. 2000 to Now | 8.3% | -28.0% | 15.6% |
| Pop. 1990 to Now | 15.3% | -31.1% | 30.8% |
| space4 | | | |
| Population Density | 1,789.5 | 1,427.6 | 93.4 |
| Land Area | 8.6 | 0.1 | 3,531,905.4 |
| Water Area | 0.2 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Yankton, SD | Fordyce, NE | United States |
| Age 0 to 4 | 5.9% | 11.1% | 5.9% |
| Age 5 to 9 | 5.2% | 2.9% | 6.1% |
| Age 10 to 14 | 6.5% | 6.8% | 6.6% |
| Age 15 to 17 | 3.7% | 11.6% | 3.9% |
| Age 18 to 20 | 3.5% | 1.9% | 4.0% |
| Age 21 to 24 | 6.5% | 4.3% | 5.2% |
| Age 25 to 34 | 11.0% | 14.5% | 13.8% |
| Age 35 to 44 | 12.9% | 11.6% | 12.9% |
| Age 45 to 54 | 11.3% | 1.9% | 12.6% |
| Age 55 to 59 | 5.7% | 8.7% | 6.7% |
| Age 60 to 64 | 7.4% | 6.3% | 6.3% |
| Age 65 to 74 | 10.4% | 12.1% | 9.6% |
| Age 75 to 84 | 7.0% | 4.3% | 4.5% |
| Age 85 and over | 3.1% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Yankton, SD | Fordyce, NE | United States |
| White | 85.2% | 91.8% | 59.4% |
| Black | 1.8% | 0.0% | 12.2% |
| Asian | 0.2% | 0.0% | 5.6% |
| Native American | 3.9% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.8% | 0.0% | 3.2% |
| Hispanic | 6.0% | 8.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Yankton, SD | Fordyce, NE | United States |
| Married Population | 47.8% | 64.0% | 49.8% |
| Currently Married | 46.7% | 54.3% | 48.0% |
| Married but Separated | 1.1% | 9.8% | 1.8% |
| Single Population | 52.2% | 36.0% | 50.2% |
| Never Married | 35.2% | 24.4% | 33.8% |
| Divorced | 10.6% | 3.0% | 10.8% |
| Widowed | 6.5% | 8.5% | 5.6% |
| space5 | | | |
| Household Size | 2.15 | 2.56 | 2.60 |
| Households | 6,577 | 81 | 124,010,992 |
| Family Households | 3,618 | 52 | 80,755,759 |
| Married couple, w/children | 29.7% | 30.8% | 30.5% |
| Married couple, no children | 47.9% | 50.0% | 42.9% |
| Non Family Households | 2,959 | 29 | 43,255,233 |
| Single householder, w/children | 16.9% | 19.2% | 15.8% |
| Single householder, no children | 5.6% | 0.0% | 10.8% |