Last seen: May 21, 1990
Mark Sheffield, a 32-year-old former Air Force mechanic and survival enthusiast from Flagstaff, Arizona, disappeared while on a solo backpacking trip through the Apache-Sitgreaves National Forest. Known to friends as meticulous and well-prepared, Mark had planned the weeklong excursion meticulously, with gear logs, maps, and a planned radio check-in schedule.
He entered the forest via the Hannagan Meadow trailhead on May 17, 1990. His final radio message, sent the night of May 21, simply said, "All quiet, just me and the woods tonight." It was the last time anyone heard from him.
When Mark failed to check in as scheduled on May 23, his brother alerted the Apache County Sheriff's Department. Search teams began sweeping the area where Mark had indicated he would travel, but the vastness of the forest and poor weather hampered the effort.
Five days into the search, a ranger discovered a small cairn of stones not marked on any trail maps. Beneath it lay a worn bandana, confirmed by the family to be Mark’s. No other signs were ever found no tent, no gear, no remains.
Given Mark's extensive training, some believe he met with foul play or stumbled into an uncharted danger. The forest contains numerous old mining shafts, and some suspect he may have fallen into one. Others suggest a more unusual fate, noting that his journals left with his roommate often referenced "the silence beyond the trees."
Official records list Mark Sheffield as missing, presumed dead. His family continues to mark May 21 each year with a radio broadcast, calling out to him on the same frequency he used during his final trip.
Page last updated: May 1995
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