Kelly (voiced by Toddy Walters) first appeared in "Rainforest Schmainforest". She fell in love with Kenny in this episode, but she didn't want to get close to him since they live on the opposite sides of the country. She did get close to him, though, and, as depicted in "Spontaneous Combustion", their relationship continued to the point where Kenny was taking frequent bus trips to see her. Despite this, she never gets Kenny's name right due to his mumbled speech, referring to him with similar-sounding names such as "Lenny", "Benny", etc.
She has a bad nose-picking habit.
She has blonde hair tied back in a ponytail, and wears a blue sweater with green trimming, and a flower embroidered on one side, and dark blue pants. The band which ties her hair back is mid-green.
She apparently knows CPR, because in "Rainforest Schmainforest", she saved Kenny from dying after he is struck by lightning, by giving him mouth-to-mouth resuscitation. Because of this act, Kelly should be noted as the first character on the show to actually care about Kenny's death, she question "who" Stan and Kyle are talking about when they say "They killed Kenny," and says they should do something to try and help him. (the concept of which is utterly lost of Stan and Kyle)
She also must have at least some talent in singing and dancing, as she sang and danced in the "Getting Gay With Kids" choir.
Cartman refers to a nose-picking character named Kelly Nelson in "Miss Teacher Bangs a Boy"; whether she is the same character as Kelly from "Rainforest Schmainforest" is debatable.