Petit Bois Island is an island off the coast of the U.S. state of Mississippi ( Mississippi Gulf Coast), south of Pascagoula. It is part of Jackson County, Mississippi. Since 1971 it has been a part of Gulf Islands National Seashore, administered by the U.S. National Park Service.
Petit Bois Island is located at United States Geological Survey, variant names are l'Isle de Petit Bois (French, modern spelling would be l'île) and Petitbois Island.. According to the
Petit bois in French means "little woods". The island was so named by the early French explorers due to a small wooded section located on the eastern end of this mostly sand and scrub-covered island. Following the island's inundation during Hurricane Katrina, most of the trees comprising the little woods section have died.
A French exploration map of 1732 showed an elongated barrier spit between Petit Bois Island and Dauphin Island  This connection was breached between 1740 and 1766, possibly as the result of the 1740 hurricane. 
Petit Bois originally extended about 7 miles (11 km) east of the Alabama-Mississippi state line and was effectively located in both states. From 1933 to 1968, the eastern end of the island eroded (due to the effects of hurricanes and natural shoreline movement) until it was 1⁄2 mile (0.8 km) west of the Mississippi state line. The island is approximately 6 miles (9.7 km) long and serves as a habitat for gulls, terns, plovers, alligators, and other wildlife.
Early maps suggest that the Petit Bois – rather than current Dauphin Island – may have been the location where a large pile of human skeletons was discovered in 1699, leading to the name Massacre Island. 
- Morton, Robert A. (2007). "HISTORICAL CHANGES IN THE MISSISSIPPI-ALABAMA BARRIER ISLANDS AND THE ROLES OF EXTREME STORMS, SEA LEVEL, AND HUMAN ACTIVITIES" (PDF). U.S. Geological Survey. Retrieved 2016-03-10.
- Horn of Plenty: Seasons in an Island Wilderness. Univ. Press of Mississippi. p. 23. ISBN 978-1-61703-410-7.
- "Petit Bois Island". Geographic Names Information System. United States Geological Survey. Retrieved 2006-04-13.
- GEMS – Petit Bois Island. Retrieved on 2009-1-28.
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