A Bitterroot Valley woman apparently died of a heart attack while riding her horse northwest of Stevensville.

Ravalli County Sheriff Chris Hoffman identified the woman as 68-year-old Gertrude Hanson of Florence. Her body was found Tuesday at about 1:30 p.m. She had been on a horse and hiking trail west of the horse trailer parking lot at the Larry Creek recreation area, according to a sheriff's office press release.

Undersheriff Perry Johnson said the investigation is still open, but there were no other injuries. Her horse was found grazing nearby.