I've been over Forge Mountain several times, but stayed away from putting the hike on hikingupward because the start of the trail is a little hard to follow. Here is how it works.
Start in the same parking lot where the swinging bridge at the beginning of the Jump Mountain hike. Instead of crossing the bridge, head back to VA 39 and cross the road. Directly across the road you may see a white blaze. That blaze signals the Guy's Run Trail. You are going to follow that up a little valley for a couple hundred yards before the trail cuts diagonally out of the valley to the right. It may be hard to see. You'll go up about 20 feet in elevation and level out in a somewhat swampy area. You should see some cut logs in the area.
|Trail start as seen from VA 39.|
As you approach Forge Mountain, it can also be a problem following the trail again. I remember my first time going through a downed tree that had been sawed - it was obvious that I was on the trail. But I could not tell where the trail went next. After a while I figured it out - it cut up the slope to the right at an angle and then switchbacked to the left. You may see some white blazes, but really, you need to feel for the trail here. Once you get past here, though, the rest of the trail is pretty easy to follow.
|T Intersection. Take a left onto a woods road.|
At 0.4 miles from your car, the Guy's Run Trail comes to a T intersection at an old road. To the right, the trail goes out to the Guy's Run Road, which climbs all the way to the summit of Big Butt Mountain. It can be a great way to return to this point., instead of retracing over Forge Mountain.
For now, take a left on the road, which is the beginning of the Forge Mountain Trail. It continues for a while and then cuts right, heading directly up Forge Mountain. The climb can be steep at times.
At 0.8 miles, keep an eye to the left of the trail for a sign telling you about a side trail to a small overlook that has a view of Lake Merriweather to the north - which is surrounded by Boy Scout camps from the DC area. The viewpoint could use some trimming.
|See the sign on the left for the overlook.|
|View from first overlook.|
Other than that, you will head straight up Forge Mountain without switchbacks. During the warmer months, you will notice a lot of Sassafras along the climb.
|Sassafras defines the trail.|
At 2.2 miles, you will have crested and begin to see an overlook on the left. Stay away from the edge at first, as the overlook is better 50 yards further. Be sure to stop - this is the money spot of this hike, with views east of Big Butt Mountain and beyond to the Blue Ridge.
The Forge Mountain Trail continues past this overlook to crest near the eponymous rock, shown above, before dropping down to an area cleared for power lines at 3.1 miles. There is a trail under the power lines, and a trail continues on the other side. That trail is easy to see during the winter but much harder to see during the growing seasons.
There are many options past this point, and I've now taken all of them. To the right, you can follow the trail under the power lines, It takes you to some great views before dropping precipitously as a bushwhack to Guy's Run Road and the other end of the Guy's Run Trail.
|Near the summit of Big Butt Mountain, a trail heads back to Forge Mtn.|
To the left, the trail under the power lines takes you down to the Laurel Run Road, which comes out on 39 at the picnic shelter in Goshen Pass.
Going straight across the power lines will take you to the Cooper's Knob Trail, also white blazed. It can be hard to find in growing season - I did not find it the first time I hiked this area in October, but when I hiked it in mid-March, it was very easy to see. This trail climbs over Cooper's Knob then drops down to a road at 4.1 miles. This road, to the right, connects with the Guy's Run Road and to the left, summits the 3451 foot high Big Butt Mountain at 5.9 miles. The Big Butt summit, though now tree covered, once included a fire tower which must have had a commanding view of many surrounding counties. Near the top of Big Butt is another trail, which heads back north towards the power line cut. It is essentially a bushwhack, though it contains occasional white blazes, as shown below.
|Ridge coming down from Big Butt Mountain seems like a blazed bushwhack.|
If you take this route back from Big Butt summit, be sure to stay on the ridge top. After a while, the road that seems to be the trail cuts right (east) down the mountain - do not follow this! Staying along the ridge, you will sometimes see a trail and sometimes not, until you reach the power lines. Turn left (west) and follow the power line road down to Laurel Run. There is a road here which could take you out to a shuttle vehicle on 39 (by far the best option!), or you could climb the power line road back up to the end of the Forge Mountain Trail. This climb is brutal! If you do this, be sure to follow the road behind the metal gate to the right. I am not sure where the road to the left goes.
|Under the power lines.|
A hike up Forge Mountain, over Cooper's Knob, summitting Big Butt Mountain, then following the ridge back to the power lines and back to the Forge Mountain trail, is 12.8 miles with 4075 feet elevation gain. The elevation profile is shown below.
A hike up Forge Mountain, then down the power line cut to Guy's Run Road and looping back to the beginning of the trail via the Guy's Run Trail, is shorter and easier at 7.9 miles, though the drop off of the mountain is a steep bushwhack. The Guy's Run Trail is not marked from the Guy's Run Road, but it starts as a gated road on the right, next to a campsite, that quickly crosses Guy's Run.
|Looking down at Guy's Run from Forge Mountain, under the power lines.|