Southeast of Harrisburg near Murphysboro in the Shawnee National Forest, there are several hiking trails through the Garden Of The Gods, a 3,300 acre wilderness area with old-growth forest. The 5.5 mile Garden Of The Gods Trail is especially nice.
To reach the trailhead from US57 in Marion, use Exit #54. Head east on SR13 for 22.3 miles into Harrisburg. Turn right heading south on SR45 for 0.8 miles. Turn left heading south on SR34 for 14.7 miles. Turn left heading east on Karbers Ridge Road for 2.7 miles. Turn left heading north on State Forest Road 250E (sign broken) for 1.2 miles. Turn left heading west on Garden Of The Gods Road (unsigned) for 0.6 miles. The hiker trailhead parking area is on the left.
Overall, Garden Of The Gods is the 3rd most popular hiking trail of all 17 hikes in Illinois.