Siouan languages
Authors who call the entire family "Siouan" distinguish the two branches as "Western Siouan" and "Eastern Siouan" or as "Siouan-proper" and "Catawban". Others restrict the name "Siouan" to the western branch and use the name "Siouan–Catawban" for the entire family. Generally, however, the name "Siouan" is used without distinction.
Ohio Valley Siouan languages
They are called "Ohio Valley Siouan" languages because of a speculative origin along the Ohio River, but only the Tutelo and the Saponi historically dwelled near there; they possibly migrated to the Roanoke River from the region of the Big Sandy River just prior to European contact. The Biloxi and the Ofo lived far to the south, along the Mississippi River.