Welcome to Hell's Hollow, a fun waterfall hike inside of McConnell's Mill State Park, located in Slippery Rock Twp., PA. (approx. 40 miles north of downtown Pittsburgh) Hell's Hollow is a flat trail, easy terrain with options for more challenges. You can hike to the falls, enjoy, and head back -or- you can cross the water and go a bit further, jumping over downed trees and climbing rocks like we did! We had SO much fun. We are avid waterfall chasers and when we hear the heavy rains, we…