1803

The United States acquires the South Dakota region with the $15 Million Louisiana Purchase from France. 1804

Meriwether Lewis and William Clark travel through the South Dakota region.

1825 Teton Sioux sign a peace treaty with the United States. 1832

Fort Pierre is built as a trading post.

1857 Sioux Falls is established.

1858 Yankton Sioux sign away most of their land to the United States.

1861

Congress organizes the Dakota Territory. 1866 Red Cloud’s war begins.

1868 Laramie Treaty creates a Sioux reservation west of the river.

1872 Dakota Southern Railroad reaches South Dakota. 1874

General Custer discovers gold in the Black Hills. 1876

The Sioux War begins in South Dakota. 1885

South Dakota adopts the official seal. 1889

South Dakota becomes the 40th state on November 1. 1890

A massacre takes place at Wounded Knee.

1918 South Dakota grants voting rights to women.

1924 Meridian Bridge was built. This was the first bridge across the Missouri. 1927

Carving begins at Mount Rushmore. 1934 Indian Reorganization Act passes.

1939

Work begins on Crazy Horse Monument. 1941

USS South Dakota is highly decorated for its service in World War II. 1959 Belle Fourche is named the geographical center of the United States.

1992 Legislature adopts the state flag.