1100-1150 - Mandan migration up the Missouri River

        In aboriginal times, the Missouri River featured rich bottoms bottomlands that were replenished each year by alluvial silts when the river flooded in the spring.  Unusually wet centuries between 800 and 1200 a.d. encouraged settlement of the Great Plains by semi-sedentary tribes of horticulturists - like the Mandan - who could now thrive in streamside settlements in an area that was formerly hostile to all but robust nomadic hunters.  The Mandans, who occupied villages of dome shaped 'earthlodges' for hundreds of years, grew 'gardens' that were legendary in pre-Columbian America.

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         Archeologists now believe the Mandans lived in the southeastern regions of the continent, probably in close proximity to the Gulf Coast, before they began migrating up the Missouri.  At that time, their eventual neighbors, the Hidatsa, were living in what is now Manitoba, while the Arikara roamed the high plains with the Pawnee. Click here for more