A nice trail along the rim of Alum Cave Hollow.”
— Zack Butler
The trail starts out to the southwest, then swings northwest and parallels the plateau edge overlooking Alum Hollow. At about 0.7 miles, the trail descends into a shallow hollow and crosses a creek that drains from Sky Lake at the Madison County Nature Trail. The creek is fairly shallow and only a few feet wide, but some folks will want to try out the improvised bridge of three narrow logs lashed together.
After crossing the creek, the trail heads uphill at a gentle slope to top out again and winds toward the southwest. When the Huntsville Motor Speedway is open, this will not be a quiet ride in the woods, but there’s a nice open feel to this trail, as there are very few invasive plants such as privet or bush honeysuckle on this part of the mountain. The forest here is mostly young hardwoods, with some pine groves.
Around one mile, the trail again descends rather steeply into a hollow, with another creek draining from north to south. The second creek, which drains the southwestern portion of Green Mountain, cascades down around 20 feet into a wide, shallow plunge pool. If you take the side trail to the south, you'll come to Alum Cave, an impressive overhang that’s more of a rock shelter than a subterranean cave. Prehistoric people used this rock shelter from 10,000 B.C. to about 500 A.D.
Backtracking back up the side trail, you can hike across the creek below the waterfall. This section of the trail is not recommended for cyclists! A line of rocks makes it easy to hike cross the creek downstream of the waterfall, and you can squeeze along a bank of wildflowers and drop into another depression where a narrower secondary creek drops over a ledge to form a smaller waterfall.