• The Ohio River: Begins at the confluence of the Allegheny and Monongahela rivers at the Point in Pittsburgh, PA, and flows 981 miles to join the Mississippi at Cairo, Ill. 
  On August 31, 1803, Lewis departed Pittsburgh, Pennsylvania with the 55 foot keelboat. 

• The Missouri River: Begins at the Gallatin, Madison, and Jefferson Rivers in Montana, to the Mississippi River, at St. Louis.  On May 14, 1804, the Corps of Discovery began their journey up the Missouri River.
   DID YOU KNOW?  The Missouri River is the longest river in the United States at 2,540 miles.  The Mississippi River is second at 2,340 miles.  Read more >>

Discover One of America's National Treasures on the Missouri River  >>
 

• The Salmon River: The Salmon River, dubbed the "River of No Return", remains one of the few remaining free-flowing waterways in America and flows for 425 miles from the headwaters in central and eastern Idaho mountains.  Salmon River Reconnaissance by Captain Clark on August 19, 1805

• The Clearwater River &  Lochsa River: Flows along US highway 12.  The Lolo Trail, route traveled by Lewis and Clark in 1805 & 1806, parallels Highway 12 along the upper ridges. 

• The Snake River: 1,040 miles long, chief tributary of the Columbia River.  Was called Lewis' River
   ( October 10, 1805).  View map >>

• The Columbia River:  Flows for more than 1,200 miles, from the base of the Canadian Rockies in southeastern British Columbia to the Pacific Ocean at Astoria, Oregon, and Ilwaco, Washington.  On October 16, 1805, Lewis and Clark entered the waters of the Columbia.

• The Yellowstone River:  The longest undammed river in the contiguous United States, retains most of its natural habitat characteristics and flows.  554 miles long from the Wyoming boundary to the North Dakota boundary.   William Clark explored the Yellowstone in 1806.

 For Educators

Teaching & Lesson Plans
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Learning Page
(Library of Congress)