Mourners held pink balloons and lit rows of pink candles in memory of the 16-year-old girl.
"She was very pretty. She was always nice to everybody. She's very caring, she always looked out for her friends. She was a good person," said classmate Amanda Outen.
Police say it happened on Friday after the parade that celebrated the Mount Vernon High School varsity boys basketball team's state championship win.
Police say the high school cheerleader was stabbed to death and another teen was hurt near Gramatan and East Prospect avenues.
Investigators have not released any names.
Those at the vigil say the teen who was killed was a friendly, caring and dedicated to her friends.
Mount Vernon police say they've arrested a 15-year-old who's now charged with manslaughter, assault and attempted assault, all of which are felonies.
The district attorney's office says the teen suspect is due back in court on April 11.