There is only one mapped stand of the Acidic Oak - Hickory Forest in Harpers Ferry National Historical Park. It’s in the Maryland Heights area, on a rounded (convex) west- to southwest-facing lower slope. If you are hiking the Maryland Heights Trail (green blaze), you may be able to see it. It's on the upslope side of the trail, not far from the trailhead, as it parallels Harpers Ferry Road and makes a major curve around a steep hillside. This hillside overlooks the Potomac River upstream of where the Potomac and the Shenandoah join.

Map tip: To better see where this occurs, go to the interactive map of Harpers Ferry NHP and search for "acidic oak."