From a total population of 10,010, Spearfish has a median age of 33.5. The average age of males, in Spearfish, is 31.7 while the average age of females is 37. When you compare this to median age of South Dakota, Spearfish is 3.3 years younger.
The median income of individuals, in Spearfish, is $26,813 while the average household income is $39,758. When comparing the median income of people living in Spearfish to the rest of South Dakota, the average income in Spearfish is $502 more.