What scientific expedition from the Mississippi River to the Pacific Ccean marked the map for the Louisiana Purchase?
The party of nearly 30 –including Lewis and Clark, three sergeants, 22 enlisted men, volunteers, interpreters, and Clark’s slave — departed St. Louis in May 1804 heading up the Missouri River. They would spend their first winter at Fort Mandan at the present site of Bismarck, North Dakota. It took about 3 weeks to build Fort Mandan, which they named for the local natives, and they settled in on Nov. 27, 1804. There, they acquired a guide and translator, the Shoshone woman Sacagawea. In spring 1805, they continued to the headwaters of the Missouri River, struggled across the Continental Divide, and headed west along the Salmon, Snake, and Columbia rivers to the Pacific. They returned to St. Louis the following year.
