The Nation Mandan, Hidatsa and Arikara , also called the Three Tribes Affiliated is an Amerindian group formed by the union of the people Mandan, Hidatsa and Arikara, from which the fatherland extended in the basin Missouri River in Dakotas.

The forced tests and displacements gathered them at the end of the nineteenth century. Today, the group is centered on the reserve of Strong Berthold in the North Dakota.

The current chief of the tribe is Tex G. Hall, which took its functions in 1998.