Who was the chief leader of the Sioux during their conflicts with the U.S. Army in the 1870s?

The chief leader of the Sioux during their conflicts with the U.S. Army in the 1870s was Sitting Bull. He played a crucial role in the resistance against U.S. encroachment on Sioux lands, particularly during the Great Sioux War of 1876. Sitting Bull was instrumental in rallying the Sioux tribes and was a prominent figure at the Battle of Little Bighorn, where the combined forces of the Sioux, including Crazy Horse, achieved a significant victory against General Custer's troops. His leadership not only inspired the Sioux warriors but also helped draw national attention to the injustices faced by Native Americans during this turbulent period.

While Crazy Horse was also a significant leader and played a key role alongside Sitting Bull, it was Sitting Bull's overall leadership and his role as a spiritual and political leader that distinguished him during this time. Other figures like Tecumseh and Chief Joseph were involved in conflicts with U.S. forces as well; however, their actions were in different contexts and timeframes. Tecumseh was active in the early 19th century, while Chief Joseph is best known for leading the Nez Perce in their struggles in the 1870s, but did not have the same direct involvement with the Sioux