Grateful acknowledgment is made for permission to use the following:

Cover art by Mike Heath | Magnus Creative.

Meriwether Lewis, collection of the New-York Historical Society, 1971.125.

William Clark, portrait by Charles Willson Peale, courtesy of Independence National Historical Park.

William Clark’s journal, ink on paper, elk skin, Missouri History Museum, St. Louis, 26081.

Clark’s field notebook, sketch of a boat, Beinecke Rare Book and Manuscript Library, Yale University.

Meeting at Council Bluffs, woodcut, by Patrick Goss, North Wind Picture Archives.

Young Omahaw, War Eagle, Little Missouri, and Pawnees, by Charles Bird King, Smithsonian American Art Museum, Washington, DC/Art Resource.

Bird’s-eye View of the Mandan Village, 1800 Miles Above St. Louis, by George Catlin, ibid.

Junction of the Yellowstone and the Missouri, watercolor, by Karl Bodmer, the Granger Collection.

Lewis and Clark at Three Forks, oil on canvas, by E. S. Paxson, mural at the Montana State Capitol, courtesy of the Montana Historical Society, X1912.07.01.

Robe, buffalo skin with painted detail, courtesy of the Peabody Museum of Archeology and Ethnology, Harvard University, 99-12-10/53121, 60740433.

Pocket sextant, Science Museum/Science & Society Picture Library.

Map by Heather Saunders.