There are 16 US Post Offices in Mississippi County serving a total of 46,044 residents equating to 2,878 residents per post office. It's estimated that approximately 73,491 packages are handled across the 16 county post offices annually. Mississippi County is a county located in the U.S. state of Arkansas. As of the 2010 census, the population was 46,480. There are two county seats, Blytheville and Osceola. The county was formed on November 1, 1833, and named for the Mississippi River which borders the county to the east. Mississippi County is part of the First Congressional District in Arkansas. The Mississippi County Judge is Randy Carney. The Blytheville, AR Micropolitan Statistical Area includes all of Mississippi County. Jefferson W. Speck, a Mississippi County planter, was the Republican gubernatorial nominee in 1950 and 1952."