Before Dakota Territory (1700s–1861)
This prelude sketches the people, routes, and agreements that shaped the northern Plains before the Dakota Territory officially formed in 1861.
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1680s–1700s
Nations of the Upper Missouri
Lakota, Dakota, and Nakota (Sioux), along with Mandan, Hidatsa, and Arikara peoples, live across the river valleys and plains with earth-lodge towns, cornfields, and far-reaching trade networks.
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1700–1750
Control of the Eastern Prairie
Sioux groups press west and north, clashing with Arikara, Mandan, and Omaha for the eastern Dakota country; by late century Sioux power dominates much of the northern Plains.
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1743
La Vérendrye’s Lead Plate
French Canadian explorers bury an inscribed lead plate near present-day Fort Pierre, marking a French claim while seeking western routes; the plate will be rediscovered in the 1900s.
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1762–1803
Colonial Hands Change
Louisiana moves from France to Spain and back again; on paper empires shift, but on the ground Native nations and fur traders continue to shape the Missouri corridor.
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1803
Louisiana Purchase
The United States buys an enormous interior from France, including the lands that will become North and South Dakota, setting the stage for exploration and future settlement.
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1804–1806
Lewis & Clark on the Missouri
The Corps of Discovery ascends and later descends the river, meeting Yankton and Teton Sioux and wintering among Mandan and Hidatsa communities—mapping rivers, noting wildlife, and recording alliances.
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1810s–1820s
Fur Trade Era
Posts like Fort Tecumseh (later Fort Pierre) anchor a booming trade linking Native hunters and Euro-American companies; pelts, guns, metals, and cloth flow along the river highways.
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1831
Steamboats Reach the Upper Missouri
The Yellowstone steamboat makes it to Fort Tecumseh, proving deep-interior river navigation practical and transforming freight, mail, and travel along the Missouri.
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1830s–1840s
Missions, Maps, and First Congregations
Missionaries, surveyors, and naturalists visit posts and villages; early services, schools, and small farm plots appear near the main river crossings.
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1851
Treaty of Fort Laramie
U.S. officials and Plains tribes outline territories and promise safe passage for overland travel—agreements that will be tested repeatedly in the decades ahead.
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1858
Yankton Sioux Cession
The Yankton Sioux cede a large tract in the southeast, opening the way for towns along the Missouri and paving the path for the first territorial capital at Yankton.
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1861
Dakota Territory Established
Congress creates Dakota Territory on March 2; **Yankton** is named the first capital. The new jurisdiction spans a vast interior that soon draws steamboats, soldiers, traders, and settlers into closer contact.