http://history.sd.gov/Museum/education.aspx The Museum of the South Dakota State Historical Society offers a variety of education kits on various topics:
Lewis and Clark in South Dakota
Fur Trade: Bridging Two Worlds
http://www.sdhspress.com The South Dakota Historical Society Press publishes and sells a wide variety of South Dakota history-related books.
http://www.pbs.org/lewisandclark This site provides lesson plans, activities, timelines, maps, corps journals, and information on Indian tribes.
http://www.lewis-clark.org An expedition overview, journal excerpts, photographs, sound files, and maps are presented.
http://www.nps.gov/lecl Provided by the National Park Service, this site includes information on the Lewis and Clark National Historic Trail, state and local trail sites, and relevant books and web sites.
https://www.archives.gov/education/lessons/lewis-clark#activities The National Archives provides links to various primary source documents, teaching activities, and worksheets related to the expedition.
http://www.ndtourism.com/whatdo/activities/lewis-and-clark-trail North Dakota's Department of Tourism site traces the expedition's progress, introduces the key players, and suggests places to visit.
http://montanakids.com/history_and_prehistory/lewis_and_clark/sacagawea.htm This site offers a short biography of Sacagawea.
https://www.sdhspress.com/journal/south-dakota-history-34-1 This issue of South Dakota History focuses on several aspects of the Lewis and Clark Expedition.
https://www.sdhspress.com/journal/south-dakota-history-35-1 This issue of South Dakota History includes articles related to the Lewis and Clark Expedition's interactions with the Teton Sioux.