Advanced canoeists and kayakers often refer to the 15-mile (24 km) section upriver from Boxley as the Hailstone River.

This extremely challenging section of the river is floatable only during periods of high water and should be attempted only by those with solid whitewater skills.

The upper section has most of the whitewater rapids to be found along the river, and features dramatic karst topography including sink holes and caves, springs, and waterfalls, over 500-foot (150 m) tall sandstone and limestone bluffs, and many rock formations.

At one point, a 0.65-mile (1.05 km) hike from the river up a narrow, boxed canyon leads to a 209-foot (64 m) waterfall,[5] Hemmed-In-Hollow Falls, the highest of its kind between the Southern Appalachians and the Rockies.

The then-governor of Arkansas, Asa Hutchinson, subsequently announced a moratorium on large confined animal feeding operations in the river's watershed.

[10] In January 2020, the Arkansas Legislature struck down rules set by Hutchison banning similar operations on the river.