Its headwaters are three separate forks that begin in Kentucky and converge in Baxter, KY, located in Harlan County.

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.

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.

[5] Beyond Cumberland Falls, the river turns abruptly west once again and continues to expand as other creeks and streams feed into it.

In April 1977, Harlan, Kentucky, and many surrounding communities were inundated with floodwaters, destroying most of the homes and businesses within the floodplain of the river.

[7] Major flooding occurred along the Cumberland River at Pineville, Barbourville, and Williamsburg in early February 2020.

[8] Notes Bibliography This article incorporates public domain material from Major Flooding Inundates Southeast Kentucky Followed by Light Snow From February 6–7, 2020.