The United States of America has over 250,000 rivers. The longest river in the USA is the Missouri River; it is a tributary of the Mississippi River and is 2,540 miles long. But the biggest in terms of water volume is the deeper Mississippi River.

The longest un-dammed river in the contiguous USA is the Yellowstone River; it is 692 miles long.

     The whole drainage topography of the USA may be divided into two main subsystems, namely the Eastern systems and the Pacific systems.

     The major rivers of USA are:

• Colorado river
• Salmon River
• Arkansas River
• Gila River
• Red River
• Tennessee River
• Minnesota River
• Snake River

    The lake system of the US comprises Great Lakes of Lake Superior, Lake Erie, Lake Huron, Lake Ontario and Lake Michigan, the first four of which are shared with Canada.