John Logan Allen

Himself - Geographer

Stephen E. Ambrose

Himself - Historian

Gerard Baker

Himself - Mandan-Hidatsa

Kevin Conway

Patrick Gass

Erica Funkhouser

Herself - Writer

William Least Heat-Moon

Himself - Writer

Gene Jones

Joseph Whitehouse

Mylie Lawyer

Herself - Descendant of Twisted Hair

James P. Ronda

Himself - Historian

Murphy Guyer

William Clark (voice)

Hal Holbrook

Narrator (voice)

Sam Waterston

Thomas Jefferson (voice)

Adam Arkin

Merriwether Lewis (voice)

Matthew Broderick

John Ordway (voice)

Dayton Duncan

Himself - Writer