| PONCA | A member of the Siouan people of the Missouri river valley in NE Nebraska. |
| OMAHA | A member of the Siouan people formerly living in the Missouri river valley in NE Nebraska. |
| MAHA | A member of the Siouan people formerly living in the Missouri river valley in NE Nebraska. |
| DAKOTA | A member of the Siouan people of the northern Mississippi valley. |
| OTO | A member of the Siouan people inhabiting the valleys of the Platte and Missouri rivers in Nebraska. |
| OTOE | A member of the Siouan people inhabiting the valleys of the Platte and Missouri rivers in Nebraska. |
| OGALALA | A member of the Siouan people formerly inhabiting the Black Hills of western South Dakota. |
| IOWA | A member of the Siouan people formerly living in Iowa and Minnesota and Missouri. |
| OSAGE | ___ River, tributary of the Missouri River in the US that flows into the Lake of the Ozarks reservoi |
| HUPA | A member of the Athapaskan people of the Trinity River valley in California. |
| WALAPAI | A member of a North American people formerly living in the Colorado river valley in Arizona. |
| PIERRE | State capital of South Dakota, founded in 1880 on the east bank of the Missouri River (6) |
| NEBRASKA | State of the central US west of the Missouri River; capital, Lincoln (8) |
| YANA | A member of an extinct North American Indian people who lived in the Pit river valley in northern California. |
| SIOUXCITY | The navigational head of the Missouri River is at ____, Iowa |
| MOHAVE | This firethorn (pyracantha) cultivar is an Indian people of the Colorado river valley in Arizona, California, and Nevada (6) |
| WADI | Roll of notes one finds in river valley in Arabia (4) |
| PLATTE | ___ River, tributary of the Missouri in Nebraska, US, upon which Lexington and Fremont stand (6) |
| STLOUIS | City in Missouri below the confluence of the Missouri and Mississippi Rivers (2,5) |
| CALABRIA | Vehicle going round a lake and river valley in Italian region (8) |
