| PEOPLE | Spearfish | Westerville | United States |
| Population | 10,494 | 36,120 | 308,035,306 |
| Pop. Density | 642 | 2,896 | 87 |
| Pop. Change | 16.80% | 3.06% | 8.07% |
| Median Age | 33.3 | 41.2 | 37.3 |
| Households | 4,644 | 13,859 | 116,716,292 |
| Household Size | 2.13 | 2.51 | 2.58 |
| Male Population | 47.06% | 46.96% | 49.27% |
| Female Population | 52.94% | 53.04% | 50.96% |
| Married Population | 42.61% | 57.55% | 47.02% |
| Single Population | 57.39% | 42.45% | 52.98% |
| ESTIMATED TOTAL POPULATION BY AGE | | | |
| Age 0 to 4 | 6.40% | 5.19% | 6.56% |
| Age 5 to 9 | 4.83% | 6.12% | 6.61% |
| Age 10 to 14 | 4.71% | 6.56% | 6.71% |
| Age 15 to 17 | 2.70% | 4.50% | 4.21% |
| Age 18 to 20 | 5.78% | 3.74% | 2.95% |
| Age 21 to 24 | 14.39% | 6.37% | 7.01% |
| Age 25 to 34 | 13.25% | 9.97% | 13.33% |
| Age 35 to 44 | 9.05% | 12.21% | 13.33% |
| Age 45 to 49 | 10.78% | 15.81% | 14.61% |
| Age 50 to 54 | 10.78% | 15.81% | 14.61% |
| Age 55 to 59 | 10.45% | 15.28% | 11.84% |
| Age 60 to 64 | 10.45% | 15.28% | 11.84% |
| Age 65 to 74 | 6.97% | 7.52% | 7.05% |
| Age 75 to 84 | 6.44% | 4.52% | 4.24% |
| Age 85 and over | 4.25% | 2.21% | 1.78% |
| RACE | | | |
| White | 93.53% | 88.60% | 72.41% |
| Black | 0.41% | 6.37% | 12.61% |
| Asian | 1.11% | 2.29% | 4.75% |
| American Indian | 2.05% | 0.16% | 0.95% |
| Other | 2.91% | 2.59% | 9.28% |
| Hispanic | 2.75% | 0.00% | 16.35% |
| Non-Hispanic | 97.25% | 100.00% | 83.65% |
| FAMILY | | | |
| Married, w/children | 27.79% | 33.03% | 30.42% |
| Married, no children | 48.21% | 49.95% | 42.46% |
| Single, w/children | 15.57% | 9.54% | 14.39% |
| Single, no children | 8.43% | 7.48% | 12.73% |
| Divorced | 13.46% | 7.95% | 10.62% |
| Separated | 3.24% | 2.86% | 4.97% |
| Widowed | 8.80% | 4.30% | 6.14% |
| Now Married | 41.80% | 56.92% | 46.32% |
| Never Married | 32.70% | 27.97% | 31.95% |
