Cpt. Meriwether Lewis

Fred MacMurray

Acting

Lt. William Clark

Charlton Heston

Acting

Sacajawea

Donna Reed

Acting

Julia Hancock

Barbara Hale

Acting

Sgt. Gass

William Demarest

Acting

Charbonneau

Alan Reed

Acting

Chief Cameahwait

Eduardo Noriega

Acting

Wild Eagle

Larry Pennell

Acting

President Thomas Jefferson

Herbert Heyes

Acting

Mr. Hancock

Lester Matthews

Acting

Shoshone Woman (uncredited)

Argentina Brunetti

Acting

Crow Woman (uncredited)

Julia Montoya

Acting

Chief Le Borgne (uncredited)

Ralph Moody

Acting

Night Camp Sentry (uncredited)

William Phipps

Acting

Helmsman Cruzatte (uncredited)

Walter Reed

Acting

Tom (uncredited)

Bill Walker

Acting

Mrs. Martha Hancock (uncredited)

Helen Wallace

Acting