Before its submersion, American Island was situated between Chamberlain and Oacoma. The island — about 2 miles long and a half-mile wide — was known for its cedar groves, cottonwoods, wild berries and birds. Lewis and Clark’s Corps of Discovery were in the area when Clark wrote in his journal on September 16, 1804 that, “Capt Lewis went on an Island above our Camp, this Island is abt. one mile long, with a Great purpotion ceder timber near the middle of it.” According to local histories, fur traders who built a post here in 1811 called it “Little Cedar.” 

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Chamberlain celebrates the memory of American Island annually with a festival and campout called American Island Days. 

Fun filled family weekend with crafts, water sports, children's activities, entertainment, car show, etc.