Portions of Beall Woods State Park have been designated a National Natural Landmark as the Forest of the Wabash.

The Forest of the Wabash Natural Area within Beall Woods State Park contains trees from 64 separate species.

One of the sweetgums of this Forest is designated as the "state champion" tree as being the largest member of this species known to grow within the boundaries of Illinois.

The Forest of the Wabash was patented by the federal government to the Beall family in the early 19th century, and was owned by them as an undisturbed woodlot until the 1960s.

[1] The nearest towns with any sizable commercial infrastructure, including hotels and grocery stores, are Grayville and Mount Carmel.