This question is a bit loaded. If you ask someone like Clyde Bellecourt, a founder to the American Indian Movement, he will say that the practice of scalping was first started by Europeans. It was a way to collect on various bounties that were offered. He often cites this as the origin of the term redskin, as during the scalping process, the blood would flow over the face, making them red.
This is an idea that is often cited among activists, especially in regards to the NFL team, the Washington Redskins. I mention this because it is a point that is becoming quite popular. A few years back, I interviewed Bellecourt for a local paper as he was giving a speech at a college. In both the interview and in his speech he mentioned the same thing. It wasn’t isolated and the idea is really beginning to circulate.
Part of the reason this idea has become more popular is because there are some sources that suggest that Europeans had begun the practice thousands of years ago. Herodotus, writing in around 440 BCE, said that the Scythian soldiers would scalp their dead enemies. However, this wasn’t the same sort of scalping that we think about. The Scythians would behead their fallen enemies, and then skin the head. After being cleaned and worked, that skin would be used as some sort of handkerchief. This probably is the only real example of something like scalping happening in the old world.
In what would become the United States, scalping was somewhat common, and it was quite wide spread. The biggest evidence of this are archaeological records which show victims of scalping. Some of the key evidence appears in skeletons from the Upper Missouri Basin. And in some places it was quite common (both after and before death).
Troy Case, in An Analysis of Scalping Cases and Treatment of the Victim’s Corpses, did a study of 1000 skulls from the American Southwest, Midwest and Southeast, with the largest number coming from Crow Creek Canyon from around the 14th century, where nearly every individual exhibited evidence of scalping. The total number of people found was 486.
Other sites have been found in Arizona as well as South Dakota and Wisconsin, which all show signs of scalping.
According to Case, it was quite a common practice, and there is a lot of evidence that has been recently discovered that continues to show just how widespread and common it was.