Missouri's 6th congressional district takes in a large swath of land in northern Missouri, stretching across nearly the entire width of the state from Kansas to Illinois. Its largest voting population is centered in the northern portion of the Kansas City metropolitan area and the town of St. Joseph. The district includes much of Kansas City north of the Missouri River.

Adair County is a county located in the northeastern part of the U.S. state of Missouri. The population census for 2020 was 25,314. As of July 1, 2021, the U.S. Census Bureau's Population Estimates for the county is 25,185, a -0.5% change. Adair county seat is Kirksville. The county was first settled by immigrants from Kentucky and organized on January 29, 1841. Adair County comprises the Kirksville, MO Micropolitan Statistical Area.