Atchison Township is a township in Nodaway County, Missouri, United States. At the 2020 census, its population was 386. The town of Clearmont lies in its southwest.
Atchison Township was established in April 1845, and named after David Rice Atchison, a United States Senator from Missouri.
Sink Creek sources from the center of this township and flows westerly, passes north of Clearmont, and deposits in the Nodaway River.