AUGUSTA, Me. — She was afraid of being alone and prone to anxiety, a diminutive 66-year-old woman with a poor sense of direction, hiking the Appalachian Trail by herself, who wandered into terrain so wild, it is used for military training. She waited nearly a month in the Maine woods for help that never came.

Geraldine A. Largay chronicled her journey in a black-covered notebook that summer of 2013, and she kept writing after she lost her way, even as her food supply dwindled along with her hopes of being found. Her last entry reflected a strikingly graceful acceptance of what was coming.

“When you find my body, please call my husband George and my daughter Kerry,” she wrote. “It will be the greatest kindness for them to know that I am dead and where you found me — no matter how many years from now.”

It would be two years before a logging company surveyor stumbled upon her campsite and remains, solving a mystery that had tormented her family and defied teams of experienced searchers. Ms. Largay, a retired nurse from Tennessee, had survived nearly a month on her own — longer than many old backwoods hands thought possible — before dying of exposure and starvation.