During the winter of 1803-1804 Lewis and Clark gathered a group of forty-eight men at St. Louis. In the spring they made their way slowly up the Missouri in a fifty-five-foot keelboat and two dugout canoes, called pirogues. By late fall they had reached what is now North Dakota, where they built a small station, Fort Mandan, and spent the winter. In April 1805, having shipped back to the president more than thirty boxes of plants, minerals, animal skins and bones, and Indian artifacts, they struck out again toward the mountains, accompanied by a Shoshone woman, Sacajawea, and her French-Canadian hus-band, Toussaint Charbonneau, who acted as interpreters and guides. In June they arrived at the Great Falls of the Missouri. It took them a month to make the portage. Jagged mountains loomed ominously in the distance.
Pond believed it was possible to travel by boat nearly to the Pacific, via the Missouri and "Naberkistagen Rivers." But Pond's map included some intervening "Stony" mountains between the two rivers.
Yet Lewis, seemingly oblivious to the boulder-strewn streams and deep ravines that impeded his portage, remained optimistic. On August 10 he wrote that if the Columbia River beyond the mountains was like what he had so far encoun-tered,"a communication across the continent by water will be practicable and safe."Then he began the long climb into the Bitterroot Mountains, eventually coming to the Continental Divide near the Lemhi Pass. Beyond the summit, Lewis saw an endless range of "unknown formidable snow clad Mountains." A navigable water route through the Rockies did not exist.
On December 5, they spotted the Pacific, built Fort Clatsop, and spent the winter there. The following spring they commenced the trek home. They divided into several parties to explore more of the Rockies. On September 23, 1806, they reached St. Louis.