There are 3 US Post Offices in Claiborne County serving a total of 8,416 residents equating to 2,805 residents per post office. It's estimated that approximately 13,433 packages are handled across the 3 county post offices annually. Claiborne County is a county located in the U.S. state of Mississippi. As of the 2010 census, the population was 9,604. Its county seat is Port Gibson. The county is named after William Claiborne, the second governor of the Mississippi Territory. Claiborne County is included in the Vicksburg, MS Micropolitan Statistical Area as well as the Jackson-Vicksburg-Brookhaven, MS Combined Statistical Area. It is bordered by the Mississippi River on the west and the Big Black River on the north. According to the United States Census Bureau, this small county has the third-highest percentage of African-American residents of any U.S. county, an 84% majority of the population. Located south of the area known as the Mississippi Delta, this area was long a center of cotton plantations and related agriculture. Many African Americans have stayed here because of family ties and making the land their own. Claiborne County was the center of a little-known but profound African-American civil rights movement and struggle during the middle of the 20th century."