Diamondhead is a city in southeastern Hancock County, Mississippi, United States. The city is located just over 50 miles northeast of Ne…Diamondhead is a city in southeastern Hancock County, Mississippi, United States. The city is located just over 50 miles northeast of New Orleans, Louisiana. It is part of the Gulfport−Biloxi Metropolitan Statistical Area. In February 2012, Diamondhead was officially incorporated as a city. In the 2020 USA decennial census, the city population was 9,529.