Hancock County is the southernmost county of the U.S. state of Mississippi and is named for Founding Father John Hancock. As of the 2020 census, the population was 46,053. Its county seat is Bay St. Louis. Hancock County is part of the Gulfport–Biloxi, 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.