Big Bluff (also known as Goat Bluff or Goat's Bluff) is just south of Compton, AR in the Buffalo River National Park.
The bluff is reached by hiking down a 3 mile trail off Arkansas Highway 43. This trail joins with several other trails along the Buffalo River, including a trail leading to Hemmed-In Hollow just downstream of Big Bluff. The waterfall at Hemmed-In Hollow is reported to be the largest east of the Rockies, and west of the Appalachians.
The map (below) shows the trail from Centerpoint Trailhead to the far end of Big Bluff (the bluff is visible in the picture to the left, along the left side.)