There are 4 US Post Offices in Shannon County serving a total of 7,294 residents equating to 1,824 residents per post office. It's estimated that approximately 11,642 packages are handled across the 4 county post offices annually. Shannon County is a county located in the southern portion of the U.S. state of Missouri. As of the 2010 census, the population was 8,441. 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. Missouri's first copper mine was opened in Shannon County in 1846 and Missouri's only manganese mine was opened here during World War II. As of the 2000 census, Shannon County ranked 78th on the list of counties with the lowest per capita income and 46th on the list of counties with the lowest median household incomes in the United States, making it the poorest county in Missouri."