According to the United States Geological Survey, variant names are l'Isle de Petit Bois (French, modern spelling would be l'île) and Petitbois Island.

Following the island's inundation during Hurricane Katrina, most of the trees comprising the little woods section have died.

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.

[2] 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.