This lengthy day hike follows the Occoquan River through five regional parks: Bull Run, Hemlock Overlook, Bull Run marina, Fountainhaid, and Sandy Run. Beginning in Hemlock Overlook Regional Park from the parking area, follow the old dirt road that leads to the Bull Run - Occoquan Trailhead. The trail begins by following the Blue Trail along the side of the stream, intersecting with the Horsheshoe Trail in the lowlands. Winding through miles of cedar, spruce, pine, and sycamore forests, the trail eventually passes Bull Run Marina and moves into the mountains. Crossing streams and rivulets (your feet may get wet!) the trail eventually coincides with Wolf Run Shoals Road, and then abruptly turns right onto an old dirt road. Several miles later, again rejoining the Blue Trail, the trail comes to an end in Fountainhead Regional Park.