The Great Allegheny Passage (GAP) is one of the great American rail trails — 150 miles of crushed limestone surface running from Cumberland to Pittsburgh, almost entirely on the bed of disused railroads. Combined with the C&O Canal Towpath, it forms an unbroken 335-mile off-road route between Pittsburgh and Washington DC.
The trail starts (or ends) in downtown Cumberland behind the Western Maryland Railway station. Most cyclists ride it in either direction over four or five days, staying in small-town B&Bs along the way. The climb from Cumberland up to the Continental Divide at Big Savage is gentle but sustained — easier going east towards DC than west towards Pittsburgh.