Jamaica Bay is located on the southwestern tip of Long Island in the boroughs of Brooklyn and Queens, New York City, and the town of Hempstead, New York/hamlet of Inwood. The bay connects with Lower New York Bay to the west through Rockaway Inlet and is the westernmost of the coastal lagoons on the south shore of Long Island. Maps of the city as late as 1910 identify the bay as Grassy Bay. Jamaica Bay is located adjacent to the confluence of the New York Bight and New York Bay, and is at the turning point of the primarily east-west oriented coastline of New England and Long Island and the north-south oriented coastline of the mid-Atlantic coast. The name derives from "Jameco" for the Jameco (or Yamecah) Native Americans.
The location of Jamaica Bay combined with the rich food resources found there make it a regionally important fish, wildlife, and plant habitat complex. This geographic location acts to concentrate marine and estuarine species migrating between the New York Bight portion of the North Atlantic and the Hudson-Raritan Estuary. Shorebirds, raptors, waterfowl, landbirds, and various migratory insects are concentrated by the coastlines in both directions. These migratory species are further concentrated by the surrounding urban development into the remaining open space and open water of Jamaica Bay. Jamaica Bay and nearby Breezy Point support seasonal or year-round populations of 214 species of special emphasis and listed species, incorporating 48 species of fish and 120 species of birds.
Jamaica Bay is a saline to brackish, eutrophic (nutrient-rich) estuary covering about 101 km² (25,000 acres), with a mean depth of 4 meters (13 ft), a semidiurnal tidal range averaging 1.5 meters (5 ft), and a residence time of about 3 weeks. The bay communicates with Lower New York Bay and the Atlantic Ocean via Rockaway Inlet, a high current area that is one kilometre (0.63 mile) wide at its narrowest point, with an average depth of 7 meters (23 ft). Measurements taken during recent surveys in Jamaica Bay indicate average yearly ranges for temperature of 1 to 26 °C (34 to 79 °F), salinity of 20.5 to 26 parts per thousand, dissolved oxygen of 3.5 to 18.5 milligrams/liter, and pH of 6.8 to 9. Loadings of nutrients and organic matter into the bay from sewage treatment plants and runoff result in phytoplankton blooms and high suspended-solid concentrations which, in turn, result in turbid water and low bottom dissolved-oxygen concentrations.
Jamaica Bay is in the middle of the New York metropolitan area, and the uplands around the bay, as well as much of the Rockaway barrier beach, are dominated by urban residential, commercial, and industrial development. The bay itself has been disturbed by dredging, filling, and development, including the construction of John F. Kennedy International Airport and, earlier, the historic (and now defunct) Floyd Bennett Field. About 49 of the original 65 km² (12,000 of the original 16,000 acres) of wetlands in the bay have been filled in, mostly around the perimeter of the bay. Extensive areas of the bay have been dredged for navigation channels and to provide fill for the airports and other construction projects..
The center of the bay is dominated by subtidal open water and extensive low-lying islands with areas of salt marsh, intertidal flats, and uplands important for colonial nesting waterbirds. The average mean low tide exposes 1.4 km² (350 acres) of mudflat, 3.8 km² (925 acres) of low salt marsh dominated by low marsh cordgrass (Spartina alterniflora), and 2.1 km² (526 acres) of high marsh dominated by high marsh cordgrass (Spartina patens). The extensive intertidal areas are rich in food resources, including a variety of benthic invertebrates and macroalgae dominated by sea lettuce (Ulva latuca). These rich food resources attract a variety of fish, shorebirds, and waterfowl. In addition, two freshwater impoundments were created on Rulers Bar Hassock in the Jamaica Bay National Wildlife Refuge; the smaller 0.2 km² (54 acre) freshwater West Pond is kept as open water, and the larger 0.5 km² (120 acre) slightly brackish East Pond is controlled to expose mudflats. Some of the islands in the bay have upland communities, including grasslands consisting of little bluestem (Schizachyrium scoparium), switchgrass (Panicum virgatum), and seaside goldenrod (Solidago sempivirens); scrub-shrub containing bayberry (Myrica pensylvanica), beach plum (Prunus maritima), sumac (Rhus spp.), and poison ivy (Toxidendron radicans); developing woodland consisting of hackberry (Celtis occidentalis), willow (Salix spp.), black cherry (Prunus serotina), and tree-of-heaven (Ailanthus altissima); and beachgrass (Ammophila breviligulata) dune. Species introduced in the Refuge to attract wildlife include autumn olive (Elaeagnus umbellata), Japanese black pine (Pinus thunbergii), and Japanese barberry (Berberis thunbergii).
The salt marshes of Jamaica Bay offer prime habitat for migratory birds and other wildlife. Most of the waters and marshes have been protected since 1972 as part of the Gateway National Recreation Area. Though much improved, pollution is still a problem, and after once enjoying a world-wide reputation for oysters and supporting a vigorous fishing industry the area has been closed to shellfishing since the early 20th century as one result. The marshlands are also fast diminishing. The majority of land and water within this complex is publicly owned by the United States federal government, and the city of New York. Most of Jamaica Bay proper and portions of the uplands and barrier beach are part of the Gateway National Recreation Area. Administered by the National Park Service, it includes (in part) the 37 km² (9,155 acre) Jamaica Bay Wildlife Refuge, Breezy Point, and Floyd Bennett Field. There are several city parks within the bay complex, including Marine Park and Edgemere Park, and numerous smaller parcels of city-owned land. Portions of the wetlands and uplands are part of John F. Kennedy International Airport, owned by the city of New York and operated by the Port Authority of New York and New Jersey. Small areas in the upland buffer around the bay and on the Rockaway Peninsula remain in private residential or commercial ownership. Jamaica Bay has been designated and mapped as an otherwise protected beach unit pursuant to the federal Coastal Barrier Resources Act, prohibiting incompatible federal financial assistance or flood insurance within the unit. The New York State Natural Heritage Program, in conjunction with The Nature Conservancy, recognizes two Priority Sites for Biodiversity within the Jamaica Bay and Breezy Point habitat complex: Breezy Point (B2 - very high biodiversity significance) and Fountain Avenue Landfill (B3 - high biodiversity significance). Jamaica Bay and Breezy Point have been designated as Significant Coastal Fish and Wildlife Habitats by the New York Department of State, and the bay up to the high tide line was designated as a Critical Environmental Area by the New York Department of Environmental Conservation. Jamaica Bay was also designated as one of three special natural waterfront areas by the New York City Department of City Planning. A comprehensive watershed management plan for the bay was completed in 1993 by the New York City Department of Environmental Protection in order to better protect and restore habitats and improve water quality. Wetlands are regulated in New York under the state's Freshwater Wetlands Act of 1975 and Tidal Wetlands Act of 1977; these statutes are in addition to federal regulation under Section 10 of the Rivers and Harbors Act of 1899, Section 404 of the Clean Water Act of 1977, and various Executive Orders.
As of Spring 2003, marshland is being lost at the rate of approximately 40 acres/year. The reasons for this loss are still unclear, but one hypothesis is that the loss is the result of rising sea levels. To test this, in the hope of preventing further losses, the National Park Service plans to dredge a small area of the bay in order to build up the soil in about an acre of marsh. Opponents are concerned that the dredging may be harmful, perhaps leading to greater loss of marshland than the area saved.
Other scientists suggest that the of nitrogen pouring into the bay every day, 92% from four wastewater treatment plants ringing the bay, may be partly to blame. They hypothesize that the high levels of nitrogen may stimulate the growth of sea lettuce, smothering other plants. The excess energy may also cause smooth cordgrass to reallocate energy from its roots to its shoots, making it harder for marsh soil to hold together.
American Airlines Flight 1 crashed in Jamaica Bay on March 1, 1962, killing 95 people. In the second season episode of the American television drama series Mad Men, "Flight 1", the fictional Andrew Campbell, the father of the character Peter Campbell, is among those lost.