There are 4 US Post Offices in Carter County serving a total of 6,905 residents equating to 1,726 residents per post office. It's estimated that approximately 11,021 packages are handled across the 4 county post offices annually. Carter County is a county located in the U.S. state of Missouri. As of the 2010 census, the population was 6,265. The county seat is Van Buren. The county was officially organized on March 10, 1859, and is named after Zimri A. Carter, a pioneer settler who came to Missouri from South Carolina in 1812. Carter County is located in the Ozarks region of southeast Missouri."