Lone Horn (Lakota: Hewáŋžiča, or in historical spelling "Heh-won-ge-chat" or "Ha-wón-je-tah"), also called One Horn (c. 1790 –1877), born in present-day South Dakota, was chief of the Wakpokinyan (Flies Along the Stream) band of the Minneconjou Lakota. Lone Horn's sons were Spotted Elk (later known as Big Foot) and Touch the Clouds, Rattling Blanket Woman was his sister, and Crazy Horse was his nephew. He participated in the signing of the Treaty of Fort Laramie in 1868, which reads "Heh-won-ge-chat, his x mark, One Horn". Old Chief Smoke (1774–1864) was Lone Horn's maternal uncle. Lone Horn died near Bear Butte in 1877 from old age. After Lone Horn's death his adopted son Spotted Elk eventually became chief of the Minneconjou and was later killed along with his people at the Wounded Knee Massacre in 1890.

George Catlin paints One Horn

In 1832, George Catlin painted One Horn, at Fort Pierre, South Dakota. Back East, Caitlin wrote this description of him:

Other Lone Horns

A Lakota chief, thought to be Oglala, named Lone Horn or One Horn is recorded in Lakota winter counts. In 1834, he accidentally caused the death of his only son. Consumed by sorrow, he committed suicide by attacking a buffalo bull on foot with only a knife, and was mangled to death. Drury and Clavin's text The Heart of Everything That Is: the Untold Story of Red Cloud states that One Horn's suicide was caused by his grief over the death of his favorite wife: "But when illness took his favorite young wife, so heavy was his grief that in a kind of ritual suicide he attacked a bull buffalo, alone, on foot, with only a knife. The two-horned animal gored The One Horn to death." Lone Horn (c. 1814-1875), son of Red Fish (Oglala), served as head chief of the Miniconjou.