Quebec provincial police were called to the hill after the woman crashed into a tree while sledding.
She was pronounced dead in hospital.
Another woman was injured, but authorities do not fear for her life.
The ski slope was closed and the lights were off at the time of the accident.
Mario Boisvert, the director general of the Val Saint-Come ski hill, said the administration does what it can to prevent people from using the hill after its hours of operation.
"We have signs to tell people not to slide, not go with snowmobiles or on four-wheelers," he said. "Even if we had people doing surveillance, people could still get through. We can't do anything about this. We try, we warn people not to slide, but they don't always listen."
Investigators are meeting other people who were on the scene.
The Val Saint-Côme ski centre is open today.Suggest a correction