Shannon County is a county in the southern portion of the U.S. state of Missouri. As of the 2020 census, the population was 7,031. Its county seat is Eminence. The county was officially organized on January 29, 1841, and was named in honor of George F. "Peg-Leg" Shannon, a member of the Lewis and Clark Expedition. It is the second-largest county by area in Missouri.