In the summer of 1925, President Calvin Coolidge authorized the establishment of national forests on six military reservations. Camp Knox was included in that number and was known as Knox National Forest.

The land was administered jointly by the Agriculture and War Departments, but retained unrestricted use by the military which was still training civilians and Soldiers from the Fifth Corps Area. At that time Camp Knox comprised 31,390 acres and all but 8,730 were designated for the forest.

A forest ranger, Lewis R. Smith, was placed in charge of the management. Revenue from timber sales and agricultural leases made the forest self-supporting, with a portion of the funds being returned to the counties where it was located.

In April 1928, the executive order for the establishment of the forest was rescinded and the designation came to a close. Also that year, fire destroyed the recently vacated Camp Knox Hospital and repairs to quarters began for the arrival of the Third Field Artillery to the post.