Charles Shiels Wainwright (December 31, 1826 – September 13, 1907) was a produce farmer in the state of New York and an artillery officer in the Union Army during the American Civil War. He played an important role in the defense of Cemetery Hill during the July 1863 Battle of Gettysburg, where his artillery helped repel a Confederate attack. His extensive diary kept during the war is considered to be among the finest such documents from the Civil War period.