Backbone Mountain is the highest mountain in the state of Maryland. Most people who climb it are state highpointers. That notwithstanding, it is a nice easy hike with a fairly decent view at the top.
From I-68, get off at exit 14, take US 219 South. Once you pass the junction with US 50 at Redhouse, MD, continue 4.3 miles to the village of Silver Lake, West Virginia(yes, you're in West Virginia; not Maryland anymore). In Silver Lake, WV, State Route 24 junctions to the west. From the junction, continue following US 219 South for 1.1 miles. On the left side of the road you will see some trees with orange blazes. Also, the back of one of the highway signs is marked "MD HP" There is a green sign with white lettering on 219 and there are parking areas on both sides of the road. The cable across the logging road had been cut, but I do not recommend driving up this logging road because it is rough and probably not legal.
Once you reach the trailhead, follow the logging road for about 20 minutes, always noting that you follow the the orange blazes on trees. A few hundred yards into the hike, you will see a red sign pointing to the left-this is NOT the correct left-hand turn. After around 3/4 of a mile on the logging road, a footpath junctions to the left of the logging road. Follow this well-cairned path a short distance where it temporarily divides, the right path being grassy, and the left path being rocky. The two paths converge back together very shortly and shortly thereafter, you find yourself at the summit of Maryland's highest mountain. There is a sign commemorating this highpoint. Some of the trees to the east have been cut so that you have a decent view to the east. There is also a picnic table where you can rest after this not-so-strenuous 1 mile, 700 vertical foot climb.
The summit and the area closeby is on private property owned by a coal company. Be sure to stay on the trail, do not litter or camp, and respect the landowner's rights so that we can continue to enjoy access to this mountain.
The land on the West Virginia side is national forest, but the summit and its immediate surrounding area are owned by a coal company which allows access but not camping.
For nice camping areas, I would recommend checking out Blackwater Falls State Park, about 10 miles south into the state of West Virginia. There are many campsites, and many hiking trails. There are a total of 15 waterfalls in the park.
If you're going to go all the way out here to climb this mountain then you should stop and see the self proclaimed smallest church in the lower 48. Seats 12. It is right along 219 in Silver Lake, WV.