Gulf Islands Wilderness
Gulf Islands Wilderness lies approximately 10 miles off the Mississippi mainland coast, as part of the last surviving portions of an ecological continuum of long, narrow barrier islands that once extended from Cape Cod to Mexico. The wilderness islands are surrounded by the Mississippi Sound to the north and the expanse of the Gulf of Mexico to the south.
Gulf Islands Wilderness are dynamic coastal features within a larger barrier island ecosystem of the Gulf Islands National Seashore that is migrating westward. Petit Bois Island is roughly 6 miles long and the eastern-most barrier island in the Mississippi District of the national seashore. West of Petit Bois Island is Horn Island, separated by Sand Island and Pascagoula shipping channel. Horn Island is the largest island, about 13 miles long, in the Mississippi District.