| | Viborg, SD | Westmont, CA | United States |
| Population | 754 | 35,913 | 329,725,481 |
| Female Population | 55.2% | 53.0% | 50.5% |
| Male Population | 44.8% | 47.1% | 49.5% |
| Median Age | 51 | 31.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 785 | 31,301 | 309,327,143 |
| Population - 2000 | 832 | 31,623 | 285,036,114 |
| Population - 1990 | 763 | 31,044 | 251,960,433 |
| Pop. 2000 to Now | -8.3% | 4.6% | 15.6% |
| Pop. 1990 to Now | 0.0% | 6.6% | 30.8% |
| space4 | | | |
| Population Density | 1,880.3 | 19,433.4 | 93.4 |
| Land Area | 0.4 | 1.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Viborg, SD | Westmont, CA | United States |
| Age 0 to 4 | 3.4% | 7.4% | 5.9% |
| Age 5 to 9 | 3.6% | 8.6% | 6.1% |
| Age 10 to 14 | 7.0% | 9.5% | 6.6% |
| Age 15 to 17 | 3.6% | 4.4% | 3.9% |
| Age 18 to 20 | 0.0% | 3.8% | 4.0% |
| Age 21 to 24 | 10.3% | 5.7% | 5.2% |
| Age 25 to 34 | 6.9% | 15.4% | 13.8% |
| Age 35 to 44 | 8.9% | 13.9% | 12.9% |
| Age 45 to 54 | 8.4% | 12.2% | 12.6% |
| Age 55 to 59 | 6.8% | 5.0% | 6.7% |
| Age 60 to 64 | 6.2% | 4.8% | 6.3% |
| Age 65 to 74 | 16.8% | 5.9% | 9.6% |
| Age 75 to 84 | 6.2% | 2.9% | 4.5% |
| Age 85 and over | 11.8% | 0.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Viborg, SD | Westmont, CA | United States |
| White | 91.8% | 1.3% | 59.4% |
| Black | 0.7% | 36.4% | 12.2% |
| Asian | 0.0% | 0.1% | 5.6% |
| Native American | 2.3% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.6% | 0.2% |
| Other | 0.0% | 0.6% | 0.4% |
| Two or More Races | 0.8% | 1.1% | 3.2% |
| Hispanic | 4.5% | 59.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Viborg, SD | Westmont, CA | United States |
| Married Population | 44.3% | 33.9% | 49.8% |
| Currently Married | 42.9% | 30.0% | 48.0% |
| Married but Separated | 1.4% | 3.9% | 1.8% |
| Single Population | 55.7% | 66.1% | 50.2% |
| Never Married | 23.3% | 52.4% | 33.8% |
| Divorced | 14.2% | 9.7% | 10.8% |
| Widowed | 18.2% | 4.0% | 5.6% |
| space5 | | | |
| Household Size | 1.81 | 3.40 | 2.60 |
| Households | 369 | 10,536 | 124,010,992 |
| Family Households | 177 | 7,603 | 80,755,759 |
| Married couple, w/children | 13.0% | 25.2% | 30.5% |
| Married couple, no children | 55.9% | 15.5% | 42.9% |
| Non Family Households | 192 | 2,933 | 43,255,233 |
| Single householder, w/children | 26.6% | 38.3% | 15.8% |
| Single householder, no children | 4.5% | 21.0% | 10.8% |