Mdewakantonwan (currently pronounced Bdewákhathuŋwaŋ, also M'DAY-wah-kahn-tahn) are one of the sub-tribes of the Isanti (Santee) Dakota (Sioux). Their historic home is Mille Lacs Lake in central Minnesota, which in the Dakota language was called Mde wakan (mystic/spiritual lake). Together with the Wahpekute (Waȟpékhute – “Shooters Among the Trees”), they form the so-called Upper Council of the Dakota or Santee Sioux (Isáŋyáthi – “Knife Makers”).
Their Siouan-speaking ancestors had migrated to the upper Midwest from the area of South Carolina in the present-day United States; colonists named the Santee River in present-day South Carolina after them. Over the years they migrated up through present-day Ohio and into Wisconsin. Facing competition from the Chippewa and other eastern Native American tribes, the Santee moved further west into present-day Minnesota.
In 1687 Greysolon du Lhut recorded his visit to the "great village of the Nadouecioux, called Izatys" on the southwestern shore of the eponymous Mde Wakan [Lake Mystery/Holy], now called Mille Lacs Lake in north central Minnesota.
Originally the term Santee was applied only to the Mdewakanton and later the closely related and allied Wahpekute. (As it was a nomadic group, it was not identified by the suffixes of thuŋwaŋ – “settlers,” or towan – “village”). Soon European settlers applied the name to all the tribes of the Eastern Dakota.
In the fall of 1837, the Mdewakantonwan negotiated a lucrative deal with the US government under an "Indian Removal" treaty, whereby they were paid nearly one million dollars for the remainder of their lands in western Wisconsin. Because the Mdewakantonwan had earlier abandoned the lands due to intrusion by the Chippewa and various ecological reasons, and were effectively living in Minnesota, they effectively gained payment for land they no longer occupied.