Furnace Mountain, Jones Run & Big Run Loop

This is a 25.4-mile loop from the Madison Run boundary, over Furnace Mountain, down Jones Run and Doyles River, through Big Run, and back on Rockytop and Austin Mountain. Plan three days and two nights, with about 22 hours of hiking in total. The trail sheet's headline mileage ranges from 26.6 to 35.3 miles, but its day-by-day figures do not resolve that range. This mapped base route measures 25.4 miles and leaves out the optional one-mile Furnace summit spur and the optional 8.7-mile Brown Mountain circuit. Campsite placement on Doyles River and Big Run can shift the distance walked on each day. Obtain a backcountry camping permit through Recreation.gov before setting out; a park entrance pass is also required, and you must carry your permit. This is an experienced backpacking route with sustained climbing and repeated stream crossings.

Start early at the boundary gate. Follow Madison Run Fire Road for 0.1 mile, then climb Furnace Mountain Trail for 3.4 miles. At about 1.6 miles, an optional one-mile round-trip spur reaches the Furnace summit and its view; it is not included in the mapped distance. Continue over Trayfoot Trail, the short Blackrock Spur and 1.2 miles north on the Appalachian Trail, then descend Jones Run Trail for 2.5 miles toward the Jones Run–Doyles River confluence. The two river trails together pass three waterfalls. The itinerary places the first night downstream of the confluence; choose a campsite allowed by your permit.

From the first camp, climb 2.2 miles up Doyles River Trail, then cross Skyline Drive at Big Run Overlook and take Big Run Loop Trail down toward the valley. Continue onto Big Run Portal for the second night. Big Run is the route's long, streamside middle section, with swimming holes and fishing described along the valley. Camp locations on the Portal vary, so your campsite determines how much of that trail falls on the second versus third day.

Big Run Portal has multiple stream crossings that can reach knee to waist depth when water is high, especially in spring and after heavy rain. Treat high water as a route-changing condition, not a minor inconvenience. The trip is most demanding where steep trail travel and repeated fords coincide; check current park guidance and choose a different plan if crossings are unsafe.

Continue along Big Run Portal to Rockytop Trail, then follow Rockytop for 5.3 miles and Austin Mountain Trail for 3.2 miles. Both ridges open to mountain views; Furnace is the first major view, while Rockytop and Austin give the return day its high-ground payoff. Finish with 0.7 mile on Madison Run Fire Road back to the same boundary gate. Blackrock is also called out as a geologically interesting stretch, though the route information does not identify a particular formation.

The start is at Madison Run Boundary on Route 663, near the Route 663/708 junction. Roadside parking is on the stream side and fits about eight cars; keep gates clear. Madison Run Fire Road is closed to public motor vehicles, so start on foot from the boundary. Dogs may accompany hikers on this route when kept on a physical leash no longer than six feet.