...Hi. (South Dakota app)

In 1803, the United States purchased the Louisiana Territory from Napoleon for $11,000,000. The territory included most of the western half of the Mississippi watershed and covered nearly all of present-day South Dakota, except for a small portion in the northeast corner of the state. The region was still largely unexplored and unsettled, and President Thomas Jefferson organized a group commonly referred to as the Lewis and Clark Expedition to explore the newly acquired region over a period of more than two years. The expedition, also known as the Corps of Discovery, was tasked with following the route of the Missouri to its source, continuing on to the Pacific Ocean, establishing diplomatic relations with the various tribes in the area, and taking cartographic, geologic, and botanical surveys of the area. The expedition left St. Louis on May 14, 1804 with 45 men and 15 tons of supplies in three boats (one keelboat and two pirogues). The party progressed slowly against the Missouri's current, reaching what is today South Dakota on August 22. Near present-day Vermillion, the party hiked to the Spirit Mound after hearing local legends of the place being inhabited by "little spirits" (or "devils"). Shortly after this, a peaceful meeting took place with the Yankton Sioux, while an encounter with the Lakota Sioux further north was not as uneventful. The Lakota mistook the party as traders, at one point stealing a horse. Weapons were brandished on both sides after it appeared as though the Lakota were going to further delay or even halt the expedition, but they eventually stood down and allowed the party to continue up the river and out of their territory. In north central South Dakota, the expedition acted as mediators between the warring Arikara and Mandan. After leaving the state on October 14, the party wintered with the Mandan in North Dakota before successfully reaching the Pacific Ocean and returning by the same route, safely reaching St. Louis in 1806. On the return trip, the expedition spent only 15 days in South Dakota, traveling more swiftly with the Missouri's current. In 1855, the U.S. Army bought Fort Pierre but abandoned it the following year in favor of Fort Randall to the south. Settlement by Americans and Europeans was by this time increasing rapidly, and in 1858 the Yankton Sioux signed the 1858 Treaty, ceding most of present-day eastern South Dakota to the United States.


Deadwood, like many other Black Hills towns, was founded after the discovery of gold.
Land speculators founded two of eastern South Dakota's largest present-day cities: Sioux Falls in 1856 and Yankton in 1859. The Big Sioux River falls was the spot of a 1856 settlement established by a Dubuque, Iowa, company; that town was quickly removed by native residents. But in the following year, May 1857, the town was resettled and named Sioux Falls. That June, St. Paul, Minnesota's Dakota Land Company came to an adjacent 320 acres, calling it Sioux Falls City. In June 1857, Flandreau and Medary, South Dakota, were established by the Dakota Land Company. Along with Yankton in 1859, Bon Homme, Elk Point, and Vermillion were among the new communities along the Missouri River or border with Minnesota. Settlers therein numbered about 5,000 in 1860. In 1861, Dakota Territory was established by the United States government (this initially included North Dakota, South Dakota, and parts of Montana and Wyoming). Settlers from Scandinavia, Germany, Ireland, and Russia, as well as elsewhere in Europe and from the eastern U.S. states increased from a trickle to a flood, especially after the completion of an eastern railway link to the territorial capital of Yankton in 1872, and the discovery of gold in the Black Hills in 1874 during a military expedition led by George A. Custer.

An increasing population caused Dakota Territory to be divided in half and a bill for statehood for North Dakota and South Dakota (as well as Montana and Washington) titled the Enabling Act of 1889 was passed on February 22, 1889 during the Administration of Grover Cleveland. It was left to his successor, Benjamin Harrison, to sign proclamations formally admitting South Dakota to the Union on November 2, 1889. Harrison directed his Secretary of State James G. Blaine to shuffle the papers and obscure from him which he was signing first and the actual order went unrecorded.