Answer
Sitting Bull was killed at Standing Rock Reservation, located in present-day North Dakota and South Dakota in the United States. His death occurred on December 15, 1890, during a confrontation between the Lakota Sioux people, led by Sitting Bull, and the US 7th Cavalry Regiment. The confrontation, known as the Wounded Knee Massacre, resulted in the deaths of hundreds of Lakota people, including women and children.