Pioneer Mothers Memorial Forest, National Natural Landmark forest in Orange County, Indiana, United States.

Pioneer Mothers Memorial Forest is an 88-acre old-growth woodlot near Paoli in Orange County, Indiana. Its stands of white ash, white oak, tuliptree and black walnut include trees the Forest Service measured at 60 feet to the first limb and 50 inches in diameter at breast height. It lies within the Hoosier National Forest as a Research Natural Area and National Natural Landmark.

The Cox family managed this land from 1816 until 1940 and chose never to cut the timber. Their decision to protect the forest over more than a century allowed it to survive as an undisturbed Central Hardwood forest.

Archaeological study of the tract revealed a Native American bottomland village area, with remains dated to about 1380 CE. The name honours the pioneer mothers of Orange County, and the woodland was set aside in 1944 as a memorial to them.

A 1.3-mile hiking trail is open to the public and passes through the old-growth stand. The forest lies near Paoli in Orange County, within the Hoosier National Forest, where the Forest Service manages the parcel for research as well as recreation.

Some of the oldest trees here have diameters exceeding one meter and date back to before European settlement. These massive specimens are remnants of a forest world that once covered the entire region.