Shoshone National Forest (/ʃoʊˈʃoʊni/ shoh-SHOH-nee) is the first federally protected National Forest in the United States and covers nearly 2,500,000 acres (10,000 km²) in the state of Wyoming. Originally a part of the Yellowstone Timberland Reserve, the forest is managed by the United States Forest Service and was created by an act of Congress and signed into law by U.S. President Benjamin Harrison in 1891. Shoshone National Forest is one of the first nationally protected land areas anywhere. Native Americans have lived in the region for at least 10,000 years, and when the region was first explored by European adventurers, forestlands were occupied by several different tribes. Never heavily settled or exploited, the forest has retained most of its wildness. Shoshone National Forest is a part of the Greater Yellowstone Ecosystem, a nearly unbroken expanse of federally protected lands encompassing an estimated 20,000,000 acres (81,000 km²).

The Absaroka and Beartooth Mountains are partly in the northern section of the forest. The Wind River Range is in the southern portion and contains Gannett Peak, the tallest mountain in Wyoming. Yellowstone National Park forms part of the boundary to the west; south of Yellowstone, the Continental Divide separates the forest from its neighbor Bridger-Teton National Forest to the west. The eastern boundary includes privately owned property, lands managed by the U.S. Bureau of Land Management and the Wind River Indian Reservation, which belongs to the Shoshone and Arapahoe Indians. Custer National Forest along the Montana border is on the northern frontier. The Oregon Trail, the 19th century covered wagon route, passes just south of the forest, where broad and gentle South Pass allowed the migrants to bypass the rugged mountains to the north.

Shoshone National Forest is home to all of the original plant and animal species that were present when explorers first visited the region. The forest is notably inhabited by nearly all animal species found in North America, such as Grizzly bear, American black bear, gray wolf, bobcat, cougar, moose, and elk. Throught the forest is more than 1,300 miles (2,100 km) of hiking trails and 32 campgrounds. Within the forest there are five wilderness areas, these areas protect more than half of the total area of managed land from development.

Shoshone National Forest is named after the Shoshone Indians, who, along with other Native American groups such as the Lakota, Crow and Northern Cheyenne, were the major tribes encountered by the first European explorers into the region. Archeological evidence suggests that the presence of people in the area extends back at least 10,000 years. The forest provided an abundance of game meat, wood products, and shelter during the winter months from the more exposed high plains to the east. Portions of the more mountainous regions were frequented by the Shoshone and Sioux for spiritual healing and vision quests. By the early 1840s, Washakie had become the leader of the easternmost branch of the Shoshone Indians. At the Fort Bridger Treaty Council of 1868 Washakie negotiated with the U.S. Government for 44,000,000 acres (180,000 km²) to be preserved as tribal lands. Subsequent amendments to the treaty reduced the actual acreage to approximately 2,000,000 acres (8,100 km²) and is known today as the Wind River Indian Reservation.

In 1957, Mummy Cave was rediscovered by a local resident on the north side of the North Fork Shoshone River, adjacent to U.S. Routes 14/16/20, 15 mi (24 km) east of Yellowstone National Park. Subsequent archeological excavations in the 1960s produced evidence that the cave had been occupied for over 9,000 years. The oldest deposits in the cave yielded prismatic stone blades and other artifacts created by paleoindians and the surrounding soils were radiocarbon dated to 7,300 BC. The evidence indicates the cave was occupied from at least 7,280 BC to 1580 AD. Besides projectile points, the cave also produced well preserved feathers, animal hides and other usually perishable materials. Additionally, the mummified remains of an individual buried inside a rock cairn were unearthed, which were dated to 800 AD. Considered one of the finest paleoindian archeological assemblages in the Rocky Mountain region, the site was placed on the National Register of Historic Places list in 1981.

In the early 19th century, the forest was visited by mountain men and explorers such as John Colter and Jim Bridger. Colter is the first white man known to have visited both the Yellowstone region and the forest, which he did between 1807 and 1808. Having been an original member of the Lewis and Clark Expedition, Colter requested permission from Meriwether Lewis to leave the expedition after it had finished crossing the Rocky Mountains during their return journey from the Pacific Ocean. Colter teamed up with two unaffiliated explorers the expedition had encountered, but soon thereafter decided to explore regions south of where his new partners wished to venture. Traveling first into the northeastern region of what is today Yellowstone National Park, Colter then explored the Absaroka Range, crossing over Togwotee Pass and entering the valley known today as Jackson Hole. Colter survived a grizzly bear attack and a pursuit by a band of Blackfeet Indians who had taken his horse. The explorer later provided William Clark, who had been his commander on the Lewis and Clark Expedition, with previously unknown information on the regions he had explored, which Clark published in 1814.

Travels by fur trappers and adventurers, such as Manuel Lisa and Jim Bridger from 1807 to 1840, completed the exploration of the region. With the decline of the fur trade in the late 1840s and much of the prized beaver long since made scarce by over-trapping, few explorers entered the forest over the next few decades. The first federally financed expedition which passed through portions of Shoshone National Forest was the Raynolds Expedition of 1860, led by topographical engineer Captain William F. Raynolds. The expedition included geologist and naturalist Ferdinand Vandeveer Hayden and was guided by mountain man Jim Bridger. Though the Raynolds Expedition was focused on exploration of the Yellowstone region, several efforts to enter what later became Yellowstone National Park were impeded by heavy snows across the mountain passes such as Two Ocean Pass. The expedition finally crossed the northern Wind River Range at a pass they named Union Pass and entered Jackson Hole valley to the south of Yellowstone. Hayden led another expedition through the region in 1871. Hayden was primarily interested in documenting the Yellowstone country west of the forest, but his expedition also established that the forest was a prime resource that merited protection.

Prior to the establishment of the Wind River Indian Reservation, the U.S. Cavalry constructed Fort Brown on the reservation lands, which was subsequently renamed Fort Washakie. During the late 19th century, the fort was staffed by African-American members of the U.S. Cavalry, better known as the Buffalo Soldiers, including the second African-American graduated from the United States Military Academy, John Hanks Alexander. Chief Washakie is buried at the fort, which is located immediately east of the forest boundary. Rumor has it that Sacajawea, the Shoshone Indian who provided invaluable assistance to Meriwether Lewis and William Clark during the Lewis and Clark Expedition, is also buried here, but it is now considered that this is unlikely and that her actual burial place was Fort Lisa in North Dakota.