The 2.5-mile Mertz Grade Trail passes crosses over the East Branch of the Au Sable River twice and takes visitors through through second-growth lowland and mixed forests with low-growing plants and excellent cover for wildlife. The terrain is considered suitable for beginners, making it a perfect, relaxing day hike for all ages. The trail connects to the Old Growth Forest Trail.

The trailhead for the Au Sable and Mertz Grade trails is located across from headquarters.