Diamondhead is a census-designated place (CDP) in Hancock County, Mississippi, United States. It is part of the Gulfport–Biloxi, Mississippi Metropolitan Statistical Area. The population was 8,425 as of the 2010 census.
Diamondhead is located at 30°23′0″N 89°22′22″W / 30.383333°N 89.37278°W / 30.383333; -89.37278 (30.383444, -89.372660).
According to the United States Census Bureau, the CDP has a total area of 11.7 square miles (30.3 km²), of which 11.3 square miles (29.4 km²) are land and 0.4 square mile (1.0 km²) (3.16%) is water.