The origins of the first National Historic Landmark was a simple cedar post, placed by the Lewis and Clark Expedition on their 1804 outbound trek to the Pacific in commemoration of the death (from natural causes) of Sgt. Charles Floyd. In time, the cedar plank was replaced by a marble obelisk.Lewis and Clark Expedition Journals, The Sergeant Floyd Monument in Sioux City, Iowa, was officially designated on June 30, 1960, but for various reasons, the public announcement of the first several NHLs was delayed.
