The Marion County coroner's office confirmed that 24-year-old Meagan Toothman passed away from head injuries on Monday night, The AP reports.
The Toothman family announced yesterday that Megan would donate her organs before dying, but it is not known yet if doctors were able to operate before she died.
Meagan, a cheerleading coach, had attended the August 14 Sugarland concert with friends Jill and Jaymie Polet, who were also injured when the stage caved in after being pounded by 60mph winds.
Four people were killed in the immediate aftermath of the collapse and many others were hospitalised with serious injuries.
Sugarland have announced that they are planning a memorial concert to honour those who died in the accident.
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Watch footage of the Indian State Fair stage collapse below (contains disturbing content):