The Difficult Run stream — or river, as Google Maps refers to it — flows from Fairfax into the Potomac River near Great Falls. A trail through this gorgeous area runs alongside it, on which I hiked for the first time this weekend with the DC Hiking and Backpacking Club, as we undertook a loop starting and ending at Difficult Run, and skirting the Potomac through Great Falls Park and Riverbend Park.
I use either AllTrails or MapMyFitness to record my hikes. This time, I used MapMyFitness: Hiked 10.66 mi on 9/23/17.