To others, a true island must front on the Atlantic Ocean. In Chatham County, that makes Wassaw Island a true island and Skidaway Island a hammock. To others, Skidaway is too big to be called a hammock, so it's an island. Some biologists are trying to refine the definition by looking at water. Hammocks, they say, do not have an underlying source of water such as the Floridan aquifer or the shallower aquifers that are above it.
True islands do.
Many hammocks are part of marshland owned by the state. But some are privately owned as parts of bigger parcels of land.