United Air Lines Flight 409 was a scheduled flight which originated in New York City, New York. The final flight destination was San Francisco, California, with stops in Chicago, Denver and Salt Lake City. The aircraft operating the service, a Douglas DC-4 propliner, registration N30062, crashed into Medicine Bow Peak, near Laramie, Wyoming, on October 6, 1955, killing all 66 people on board. The victims included five female members of the Mormon Tabernacle Choir and military personnel. At the time, this was the deadliest airline crash in the history of American commercial aviation. Another 66 lives had been lost earlier that year in the March 22 crash in Hawaii of a United States Navy Douglas R6D-1 Liftmaster military transport aircraft, and 66 had also died in the mid-air collision of two United States Air Force C-119G Flying Boxcars over West Germany on August 11, placing the three crashes in a three-way tie as the deadliest aviation incidents in 1955.

Medicine Bow Peak is the highest peak in the Snowy Range, a part of the Medicine Bow Mountains, about 35 miles (56 km) west of Laramie, Wyoming. It lies within Medicine Bow National Forest and is the highest point in southern Wyoming. The summit lies in extreme western Albany County, but the mountain's lower reaches stretch westward into eastern Carbon County. The summit is 12,018 feet high and is visible from Snowy Range Pass, elevation 10,847 ft, on Wyoming Highway 130, a Wyoming Scenic Byway. The most commonly used trail to the peak is a four-mile hike featuring switch-backs and a great deal of loose rock. The trails to the peak are usually open from early June to mid October.