Clark State Forest, established in 1903, is the oldest state forest in Indiana. The original appropriations to purchase a 2,000 acre tract took place during the administration of Governor Winfield Durbin. In the ensuing 96 years, additional acquisitions have increased this area to the present 24,000 acres. Much of this land was originally part of Clark's Grant, lands provided by a clause in the Virginia Cession of Claims to the Northwest Territory on December 20, 1783.
Clark State Forest was used as an experimental forest for many years, early in the development of forestry into a science and profession. More than 150 experimental tree plantings, established from 1905 through 1935, can still be observed in many areas throughout the forest.