Biloxi is located in southeastern Harrison County, bordered to the south by Mississippi Sound (part of the Gulf of Mexico) and to the northeast partially by Biloxi Bay, which forms part of the Jackson County line. To the northeast, across Biloxi Bay, are the Jackson County city of Ocean Springs and the unincorporated community of St. Martin. The Back Bay of Biloxi continues west from the Jackson County line, crossing the city of Biloxi to Big Lake on the city's western boundary, where the Biloxi and Tchoutacabouffa rivers join. The Tchoutacbouffa flows from east to west across the city and forms part of the city's eastern boundary. Biloxi is bordered to the north and east by the city of D'Iberville and to the west by the city of Gulfport.
