There are 3 US Post Offices in Grenada County serving a total of 21,861 residents equating to 7,287 residents per post office. It's estimated that approximately 34,893 packages are handled across the 3 county post offices annually. Grenada County is a county located in the U.S. state of Mississippi. As of the 2010 census, the population was 21,906. Its county seat is Grenada. The county is named for the province of Granada in southern Spain. Its western border is formed by the Yazoo River and it fronts on the Mississippi Delta. Cotton cultivation was important to its economy well into the 20th century. The Grenada, MS Micropolitan Statistical Area includes all of Grenada County.