There are 3 US Post Offices in Hancock County serving a total of 30,769 residents equating to 10,256 residents per post office. It's estimated that approximately 49,111 packages are handled across the 3 county post offices annually. Hancock County is the southernmost county of the U.S. state of Mississippi. As of the 2010 census, the population was 43,929. Its county seat is Bay St. Louis. The county is named for Founding Father John Hancock. Hancock County is part of the Gulfport\u2013Biloxi-Pascagoula, MS Metropolitan Statistical Area. It is situated along the Gulf of Mexico and the state line with Louisiana. The area is home to the John C. Stennis Space Center, NASA's largest rocket engine test facility. The county was severely damaged from Hurricane Katrina on August 29, 2005, causing catastrophic effects."