The northern section of the Black Mountains are drained by the Cane River to the west and the South Toe River to the east, both of which are part of the upper Nolichucky River watershed. The southwestern part of the range is drained by the upper French Broad River which, like the Nolichucky, is west of the Eastern Continental Divide and thus its waters eventually wind up in the Gulf of Mexico. A few of the streams in the southeastern section of the range are part of the Catawba River watershed, and are thus east of the Eastern Continental Divide.