The hill approximately two miles south of the guardhouse was known as Sentinel Hill. As part of the Fort Hays military reservation, a sentry (guard) posted at this location could have seen several miles in all directions.
The legend of Elizabeth Polly, also known as "the blue light lady," is closely linked to Sentinel Hill. When a cholera epidemic hit in 1867, hospital steward Ephraim Polly was assistant to the fort doctor. His wife, Elizabeth, comforted patients in the hospital. When she became sick with cholera, she asked to be buried on top of the hill, but it was too rocky to dig a grave. Elizabeth is buried on the side of the hill. Sightings of her ghost were reported in 1897 and have continued to this day.