Its headwaters are three separate forks that begin in
Kentucky and converge in
Baxter, Kentucky, located in
Harlan County.
Martin's Fork starts near
Hensley Settlement on Brush Mountain in
Bell County and snakes its way north through the mountains to Baxter.
Clover Fork starts on
Black Mountain in Holmes Mill, near the Virginia border, and flows west in parallel with
Kentucky Route 38 until it reaches
Harlan. Clover Fork once flowed through downtown Harlan and merged with Martins Fork at what is now the intersection of
Kentucky Route 38 and
US Route 421. A flood control project begun in 1992 diverted it through a tunnel under Little Black Mountain, from which it emerges in Baxter and converges with Martins Fork.
Poor Fork begins as a small stream on
Pine Mountain in
Letcher County near Flat Gap, Virginia. It flows southwest in parallel with Pine Mountain until it merges with the other two forks in Baxter. From there, the wider river, now named Cumberland, continues flowing west through the mountains of Kentucky before turning northward toward
Cumberland Falls. The falls is one of the largest waterfalls in the southeastern United States and is one of the few places in the Western Hemisphere where a
moonbow can be seen. Beyond Cumberland Falls, the river turns abruptly west once again and continues to expand as other creeks and streams feed into it. It receives the
Laurel and
Rockcastle rivers from the northeast, followed by the
Big South Fork of the Cumberland River from the south. From here it flows into the man-made
Lake Cumberland, formed by
Wolf Creek Dam. The more than reservoir is one of the largest artificial lakes in the eastern US. Near
Celina, Tennessee, the river crosses south into that state, where it is joined by the
Obey River and
Caney Fork. Northeast of
Nashville, the river is dammed twice more, forming
Cordell Hull Lake and
Old Hickory Lake. After flowing through Nashville and picking up the
Stones River, the river is dammed to form
Cheatham Lake. The river turns northwest toward
Clarksville, where it is joined by the
Red River. It flows back into Kentucky at the
Land Between the Lakes National Recreation Area, a section of land nestled between
Lake Barkley, which is fed by the Cumberland River, and
Kentucky Lake. Finally, the river flows north and merges with the
Ohio River at
Smithland, northeast of
Paducah. ==History==