The 150-mile Great Allegheny Passage connects with the 184.5-mile C&O Canal Towpath at Cumberland, Maryland, creating a 334.5-mile traffic-free route between Pittsburgh and Washington, DC.The trail has a packed crushed limestone surface on abandoned rail beds, with an average grade of less than 1%. Near the Big Savage Tunnel, the trail crosses the Eastern Continental Divide. From that point going east, the trail drops 1,754 feet in 24 miles to reach Cumberland and, going west, it drops 1,664 feet in 126 miles to reach Pittsburgh. The C&O Canal towpath is less improved than the GAP. In the 128 miles from Pittsburgh, PA at 730′ feet above sea level to the Eastern Continental Divide at 2,375′ above sea level, the trail gently rises 1,665 feet. In the 22 miles to Cumberland, 625′ above sea level, it descends 1,754 feet.