Charles Nelson Clark (August 21, 1827 – October 4, 1902) was a U.S. Representative from Missouri.

Born in Cortland County, New York, Clark attended Hamilton College, Clinton, New York.

When the Civil War broke out he assisted in raising a company of cavalry, which was made Company G, 3rd Illinois Cavalry Regiment, August 6, 1861, and went directly into service.

He became interested in the Mississippi River bottom lands in Illinois and undertook their reclamation.

He died in Hannibal, Missouri, October 4, 1902.