The Kellys, from Allen, Co., Kansas, were accompanied by their niece, seven-year-old Mary J. Hurley. Fanny and Mary, with Sarah Larimer, and son, were taken captive. Mary escaped that night and found her way back to the trail near here but was overtaken and killed just as she was about to be rescued by passing soldiers. Her body was discovered and buried here a few days later.

These graves were identified and restored in 1946 by W. W. Morrison of Cheyenne. When the dam across Little Box Elder was built in 1954, the remains of the four men were removed from their original burial place in the valley and reinterred beside the grave of Mary Hurley.