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.^{[citation needed]} Over the years they migrated up through Ohio and into Wisconsin. Facing competition from the Chippewa and other eastern American Indian peoples, the Santee moved further west into present-day 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.