Bighorn National Forest, National Forest in Big Horn County, Wyoming, United States

Bighorn National Forest is a large protected forest area in Wyoming featuring mountains, valleys, and high plateaus that exceed 13,000 feet in elevation. The landscape includes steep ridges, river valleys, and diverse forest types ranging from dense pine stands to alpine meadows.

The Bighorn National Forest was established as the Big Horn National Forest on 22 February 1897, one of the oldest government-protected forest lands in the United States. On 1 July 1908 an executive order changed its name to Bighorn National Forest. By September 1981 it covered 1,115,171 acres, of which 1,107,670 were National Forest land.

The Medicine Wheel Passage (U.S. Highway 14A) crosses the forest's north and passes the Medicine Wheel National Historic Landmark, a stone circle on a ridgetop. The site is listed as a National Historic Landmark, and the road that bears its name is one of three scenic byways through the forest.

The forest provides numerous marked hiking trails, camping sites, and picnic areas accessible to visitors of different experience levels. Preparation for changing mountain weather and varying elevations is important, particularly in the higher zones where conditions shift rapidly.

Meadow Lark Lake was formed by a dam built in 1936 by Company 841 of the Civilian Conservation Corps. The forest's streams are fed mainly by snowmelt, and water sampling from its lakes shows the highest acid rain deposition of any mountain chain in the Rockies. Grizzlies were absent through most of the 20th century but have made a comeback in recent decades.