The Casselman River is a 56.5-mile-long (90.9 km) tributary of the Youghiogheny River in western Maryland and Pennsylvania in the United States. The Casselman River drains an area of 576 square miles. The river has been used for transportation across the Allegheny Mountains, between the cities of Baltimore and Washington, D.C. in the east and Pittsburgh in the west. Two railroads followed the Casselman River from Meyersdale, Pennsylvania to Confluence. First is the B&O Railroad, running between Baltimore and Pittsburgh, which was completed in 1827, and is currently owned by CSX. Second is the Western Maryland Railway, which ran from Cumberland, Maryland to Connellsville, Pennsylvania. Although the Western Maryland was abandoned in the 1980s, the right-of-way has been converted into the Gre