Park spokesman Al Nash says park rangers responded to a call from a woman Saturday morning at the Grant Village Campground who said her daughter had shot herself with a handgun.
Authorities say resuscitation efforts by emergency responders failed. Names haven’t been released.
Nash says park rangers and special park agents are conducting the investigation, and that part of the campground remained cordoned off Sunday.
Nash says he didn’t know how many family members were camping or where they are from in Idaho.
A federal law went into effect Feb. 22, 2010, allowing visitors to possess firearms in the park.
Nash says the last shooting death in the park occurred in 1978.