As the nation's largest estuary, the Chesapeake Bay contains a diverse collection of habitats and salinity regimes. In order to incorporate the diversity of habitats in the southern Chesapeake Bay subregion, CBNERRVA established four components along the salinity gradient of the York River estuary. These components: Sweet Hall Marsh (871 acres), Taskinas Creek (980 acres), Catlett Islands (690 acres), and the Goodwin Islands (777 acres) represent extensive tidal fresh water marshes, forested wetland hammocks, emergent mesohaline salt marshes, forested upland hammocks, salt-marsh islands inter-tidal flats and extensive submerged aquatic vegetation beds.