The U.S. Forest Service established the first protected "wilderness area" under its own discretion in 1924. In 1964, the Wilderness Act established the National Wilderness Preservation System, reserved to Congress the authority to designate wilderness areas, and directed the Secretaries of Agriculture and of the Interior to review certain lands for their wilderness potential. The Act also designated 54 wilderness areas with 9 million acres of Forest Service land. Congress began expanding the Wilderness System in 1968, and today, there are 631 wilderness areas, totalling nearly 104 million acres, in 44 States.