Plains Village people are living along the Missouri River valley.
The Sioux, having been pushed out of Minnesota by the Chippewa, reach the Missouri River. Enroute, they drive the Omaha from the Big Sioux River and James River valleys. Their arrival at the Missouri River ignites a long war with the Arikara for control of the Missouri River valley in central South Dakota.
The war with the Arikara comes to an end with the Sioux driving the Arikara out of central South Dakota.
By the early 19th century, the Great Sioux Nation dominates the northern Plains. This area includes most of the Dakotas, northern Nebraska, eastern Wyoming, and southeastern Montana.
The United States purchases the Louisiana Territory from France. The westward expansion that follows eventually leads to depletion of the buffalo, an animal central to the Lakota way of life.
The Fort Laramie Treaty of 1851 guarantees safe passage of settlers through tribal lands in exchange for promises of an annuity in the amount of $50,000 for fifty years, amended to $50,000 for ten years.
Red Cloud leads a successful fight to close off the Bozeman Trail, a pass leading to the gold mines of Montana. The trail crosses over the traditional hunting grounds of the Teton.
The Fort Laramie Treaty of 1868 establishes the Great Sioux Reservation, encompassing most of present-day South Dakota west of the Missouri River, including the Black Hills. The U.S. government pledges to keep non-Indian settlers out of this territory.
An expedition led by Lt. Col. George A. Custer discovers gold in the Black Hills, sending a rush of prospectors to the area. As more and more non-Indians arrive, the Native American people defend their homes and way of life.
On June 25, Custer attacks a large Native American encampment. Sitting Bull, Gall, Crazy Horse, and several Cheyenne leaders defeat Custer and the 7th Cavalry at the Battle of Little Big Horn. Custer loses his life along with his entire command of more than 200 men.
An act by the U.S. Congress in March splits the Great Sioux Reservation into six smaller reservations. Some of the tribes begin performing the Ghost Dance, a religious ceremony thought to extinguish the whites, return the buffalo, and restore the former way of life. South Dakota is admitted to the union in November.
Sitting Bull is murdered on the Standing Rock Reservation. Following this event, Big Foot and his Mnicoujou band flee to Pine Ridge to seek protection under Red Cloud. More than 250 members of Big Foot's band are massacred by the 7th Cavalry on December 29 at Wounded Knee. The event is often described as the last major conflict between the U.S. Army and the Great Sioux Nation.
Land on the Rosebud Reservation is opened for non-Indian settlement.
The first steps are taken to open large parts ot he Cheyenne River and Standing Rock Reservations to non-Indian settlement.
The Citizenship Act of 1924 naturalizes Native Americans born within the territorial limits of the United States.
The Indian Reorganization Act recognizes tribal governments as sovereign nations.
Members and supporters of the American Indian Movement (AIM) seize the village of Wounded Knee and occupy it for 71 days.
The Indian Self Determination and Education Assistance Act authorizes federal government agencies to enter into contracts with and make grants directly to federally-recognized Indian tribes. This authority gives tribes greater control over funding that affects their welfare.
South Dakota Governor George S. Mickelson and representatives of the state's nine tribal governments proclaim 1990 a Year of Reconciliation. A Century of Reconciliation is declared in 1991.
Governor M. Michael Rounds proclaims 2010 as the Year of Unity, calling for renewed efforts in understanding, cooperation and reconciliation among all races and cultures in South Dakota.