Here is another version of the story:
The story behind how Hell's Hollow got its name is more rumor than fact. It involves a Civil War soldier who somehow became lost in Slippery Rock Gorge. The gorge was a very wild place in 1860s, with bears, elk, and coyotes inhabiting the area. When the lost soldier finally found a route out of the gorge, supposedly via Hell Run, he told tall tales of how he had barely survived the journey through hell by escaping from large animals that lurked everywhere within the gorge's shadow-filled hollows... Source, Pennsylvania Waterfalls, Scott E. Brown. P. 142Obviously a variation of the previously posted stories. They do seem to be derived from the same theme; a traveler getting lost within the gorge and 'escaping' via Hells Hollow... a Dante's Inferno of sorts.
This photo was taken along the Hell's Hollow Trail in McConnells Mill on July 18, 2009.