Park City Police officers were dispatched to the Glenwood Cemetery located at 402 Silver King Drive shortly after 6 p.m.
"The headstone measures over six foot tall and weighs hundreds of pounds," says Cpt. Kirk. "It took several family members to lift it off of him."
Cpt. Kirk says they are still investigating how the tombstone fell on the boy.
A neighbor says she overheard the boy's mother telling family members that the boy was climbing on the headstone when it fell on him.
"She told her son that he was going to be okay, probably a broken arm," says Kathryn Augue.
Cheney was taken to Park City Medical Center where he died from his injuries.
"We knew it was serious when we got there," says Cpt. Kirk. "He may have suffered head injuries."
Cpt. Kirk says he was not sure what the boy's family was doing at the cemetery.
Justin Russell who lives near the cemetary saw the commotion and approached the scene.
"There's always kids playing over there," he says. "Some of the headstones are in bad shape."
Bruce Erickson, president of the Glenwood Cemetery Association says it is a private, non-profit cemetery. He says families are responsible for maintaining the plots.
Park City Medical Center spokesperson Amy Roberts later released a statement, saying, "This tragic accident has taken the life of our energetic, sweet, beloved little boy, Carson Dean Cheney. We appreciate your thoughts and prayers, but wish for privacy at this difficult time."
Roberts also released a photograph of Carson provided by the family. The photo was taken only a few minutes before the tragic incident.
Police say the boy's family is from Lehi.