Clark Township is a township in Atchison County, Missouri, United States. At the 2020 census, its population was 898.
Clark Township was established in 1845 and was one of the five original townships in Atchison County.
A ferry in the southwest of the township crossed the Missouri River to St. Deroin in Nebraska.
Clark Township covers an area of and contains one incorporated settlement, Fairfax. Two other former settlements were present: Milton and Nishnabotna
The streams of Cow Branch, Old Channel Nishnabotna River, and Rock Creek run through this township. It contains four cemeteries: Beck, Corning, Mount Hope, and Pleasant Ridge.
Deroin Bend Island, an island of the Missouri River, is partly located in the southwesternmost portion of the township but is mostly located in Lincoln Township, Holt County.
Clark Township contains one airport, Steele Airport.