The 4th Missouri Cavalry Regiment, also known as the Fremont Hussars, was a cavalry regiment that served in the Union Army during the American Civil War. Elements of the regiment fought at Pea Ridge, Whitney's Lane, Little Blue River, Byram's Ford, Westport, Marais des Cygnes, Marmiton River, and Mine Creek. Company C served at Iuka and Corinth while Company F was at Raymond, Jackson, Champion Hill, and Vicksburg.