The Ohio River, which streams westward from Pittsburgh, Pennsylvania, to Cairo, Illinois, is the largest tributary, by volume, of the Mississippi River in the United States. At the confluence, the Ohio is considerably bigger than the Mississippi (Ohio at Cairo: 281,500 cu ft/s (7,960 m/s); Mississippi at Thebes: 208,200 cu ft/s (5,897 m/s)) and, thus, is hydrologically the main stream of the whole river system. 

The river flows through or along the border of six states, and its drainage basin includes parts of 15 states. Through its largest tributary, the Tennessee River, the basin includes many of the states of the southeastern U.S. It is the source of drinking water for three million people. 

It is named in Iroquoian or ,  "Good River" or and "Spelewathiipi". The river had great significance in the history of the Native Americans, as numerous civilizations formed along its valley. For thousands of years, Native Americans used the river as a major transportation and trading route. Its waters connected communities. In the five centuries before European conquest, the Mississippian culture built numerous regional chiefdoms and major earthwork mounds in the Ohio Valley, such as Angel Mounds near Evansville, Indiana, as well as in the Mississippi Valley and the Southeast. The Osage, Omaha, Ponca and Kaw lived in the Ohio Valley, but under pressure from the Iroquois to the northeast, migrated west of the Mississippi River to Missouri, Arkansas and Oklahoma in the 17th century.

Answer the following questions:
1. How many state doe the Ohio River go through or by?
2. How many are included in it's drainage basin?
3. How many people use it for drinking water?
4. What is one of its tributaries?
5. Where does that rank in size among all its tributaries?
6. What river is the Ohio River a tributary of?
7. How is that measured?
8. Which way does it flow?
9. Beginning where?
10. Where is that?
11. Where does it end up?
12. Is that that in Egypt?
13. Where?
14. For what group is the river a big part of history?
15. What did they make along it?
16. What did it connect?
17. Did they use it for anything?
18. For what?
19. Anything else?
20. What?

Numbered answers:
1. six
2. 15
3. three million
4. Tennessee River
5. The largest
6. Mississippi
7. cu ft/s
8. westward
9. Pittsburgh
10. Pennsylvania
11. Cairo
12. No
13. Illinois
14. Native Americans,
15. civilizations
16. communities
17. yes
18. transportation
19. yes
20. trading