They are an American hate group and white supremacy organization that discriminates against African Americans and other minorities, such as Jews.
In "Pinkeye", Principal Victoria noticed Cartman dressed as Adolf Hitler. To rectify this, she tried dressed him as a ghost, but he ended up looking like a member of the KKK. When the boys went trick or treating, they received only one piece of candy as a result of the costume.
In "Chef Goes Nanners", the debate as to whether the South Park flag should be changed because of it's depictions is heating up. Because of these depictions, the KKK support the argument that the flag should not be changed. The group is shown holding a meeting in a forest.
Jimbo Kern and Ned Gerblansky attempt to infiltrate the group, in a successful attempt at convincing them to change their argument. Their reasoning is that because of the majority of the voters are against the KKK's ideologies, they will also change their votes.
After Jimbo and Ned exit the meeting, the group conducts a series of party games and other silly activities.
In "Here Comes the Neighborhood", Token Black puts in a successful advertisement in Forbes magazine to draw more wealthy residents to South Park. Upset at the potential consequences the sudden influx of wealth will have on South Park, Mr. Garrison and the other men of South Park lead a rally to drive the wealthy residents away.
At the rally, the men dress as ghosts, in order to make the town appear haunted. The wealthy celebrities mistake their costumes for KKK members and leave the town thinking it is "hated".
The typical KKK member wears a long, white robe, which covers most of their bodies. They wear black shoes and a white, pointed hat. On the robe, the group's insignia is embroidered on the left breast.