A brackish estuarine area of three major habitat types. The site and its associated wetlands lie in a climatic zone of overlap between temperate and tropical, thus supporting plants and animals many of them threatened or endangered from both zones. Due to the mix of salt and fresh water, and the productivity of the lagoon system, a high degree of biological diversity is present at both species and community levels. The refuge and adjacent waters support thousands of migratory birds in winter as well as numerous nesting species and shorebirds. Management goals include maintenance of quality habitat for endangered species, protection of nesting and feeding habitat for migratory birds, and promoting public awareness.
Shellfish harvesting is a popular activity outside the designated area.
Sand Lake National Wildlife Refuge . A large freshwater cattail marsh, it provides critical nesting and staging habitat for many different bird species. The number of migrating waterfowl using the large wetland complex often exceeds 20,000 and includes such birds as Mallards, Wood ducks and Canada geese. Sand Lake is also important habitat for reptiles, amphibians, fish, and mammals. Thousands of people from birdwatchers to anglers and hunters to hikers to school groups visit Sand Lake Refuge each year.