Biogeographic Regions

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The National Estuarine Research Reserve System is a network of protected biogeographic regions in the United States that serve as reference sites for research, education, and stewardship. Biogeographic regions are geographic areas with similar dominant plants, animals, and prevailing climate.

There are 11 major biogeographic regions around the coast with 29 subregions, 20 of which are currently represented by the reserve system. The reserve system is designed to include sites representing all 29 biogeographic subregions, with additional sites representing different types of estuaries. In the near term, priority for federal designation of new National Estuarine Research Reserves will be given to coastal states that are in unrepresented biogeographic regions.

Reserve Designation Dates, Acreage, and Biogeographic Regions

Reserve Year Acres Square
Miles
Square
Kilometers
Region
South Slough, OR 1974 4,771 7.5 19.3 Columbian (17)
Sapelo Island, GA 1976 6,110 9.5 24.7 Carolinian (7)
Rookery Bay, FL 1978 110,000 171.9 445.2 West Indian (10)
Apalachicola Bay, FL 1979 234,715 384.4 995.5 Louisianian (11)
Elkhorn Slough, CA 1979 1,439 2.2 5.8 Californian (15)
Padilla Bay, WA 1980 11,966 17.9 46.4 Columbian (19)
Narragansett Bay, RI 1980 4,332 6.7 17.2 Virginian (3)
Old Woman Creek, OH 1980 573 0.9 2.3 Great Lakes (22)
Jobos Bay, PR 1981 2,883 4.5 11.7 West Indian (9)
Tijuana River, CA 1982 2,293 3.6 9.3 Californian (14)
Hudson River, NY
(4 components)
1982 4,838 7.6 19.6 Virginian (3)
North Carolina
(4 components)
1985, 1991 10,568 15.6 40.5 Carolinian (6)
Wells, ME 1986 2,250 3.5 9.1 Acadian (2)
Chesapeake Bay, MD
(3 components)
1985, 1990 6,249 9.8 25.3 Virginian (5)
Weeks Bay, AL 1986 9,317 10.2 26.4 Louisianian (11)
Waquoit Bay, MA 1988 2,804 4.3 11.3 Virginian (3)
Great Bay, NH 1989 10,235 16.0 41.4 Acadian (2)
Chesapeake Bay, VA (4 components) 1991 3,072 4.8 12.4 Virginian (5)
Ace Basin, SC 1992 99,308 155.2 401.9 Carolinian (7)
N. Inlet Winyah Bay, SC 1992 18,916 29.6 76.6 Carolinian (7)
Delaware 1993 6,364 7.7 20.0 Virginian (4)
Jacques Cousteau, NJ 1998 116,116 179.5 464.9 Virginian (4)
Kachemak Bay, AK 1999 372,000 572.0 1,481.6 Fjord (25)
Grand Bay, MS 1999 18,049 28.8 74.5 Louisianian (12)
Guana Tolomato Matanzas, FL 1999 76,760 114.6 296.8 Carolinian (8)
San Francisco Bay, CA 2003 3,710 5.8 15.0 Californian (16)
Mission-Aransas, TX 2006 186,189 290.2 751.5 Louisianian (13)
Lake Superior, WI 2010 16,697 26.1 67.6 Great Lakes (20)
He‘eia, HI 2017 1,385 2.16 5.60 Insular - Hawaiian Islands
Connecticut 2022 52,160 81.5 211.1 Virginian (3)