01 New England Region 0101 St. John 0102 Penobscot 0103 Kennebec 0104 Androscoggin 0105 Maine Coastal 0106 Saco 0107 Merrimack 0108 Connecticut 0109 Massachusetts-Rhode Island Coastal 0110 Connecticut Coastal 0111 St. Francois 02 Mid-Atlantic Region 0201 Richelieu 0202 Upper Hudson 0203 Lower Hudson-Long Island 0204 Delaware 0205 Susquehanna 0206 Upper Chesapeake 0207 Potomac 0208 Lower Chesapeake 03 South Atlantic-Gulf Region 0301 Chowan-Roanoke 0302 Neuse-Pamlico 0303 Cape Fear 0304 Pee Dee 0305 Edisto-Santee 0306 Ogeechee-Savannah 0307 Altamaha-St. Marys 0308 St. Johns 0309 Southern Florida 0310 Peace-Tampa Bay 0311 Suwannee 0312 Ochlockonee 0313 Apalachicola 0314 Choctawhatchee-Escambia 0315 Alabama 0316 Mobile-Tombigbee 0317 Pascagoula 0318 Pearl 04 Great Lakes Region 0401 Western Lake Superior 0402 Southern Lake Superior-Lake Superior 0403 Northwestern Lake Michigan 0404 Southwestern Lake Michigan 0405 Southeastern Lake Michigan 0406 Northeastern Lake Michigan-Lake Michigan 0407 Northwestern Lake Huron 0408 Southwestern Lake Huron-Lake Huron 0409 St. Clair-Detroit 0410 Western Lake Erie 0411 Southern Lake Erie 0412 Eastern Lake Erie-Lake Erie 0413 Southwestern Lake Ontario 0414 Southeastern Lake Ontario 0415 Northeastern Lake Ontario-Lake Ontario-St. Lawrence 05 Ohio Region 0501 Allegheny 0502 Monongahela 0503 Upper Ohio 0504 Muskingum 0505 Kanawha 0506 Scioto 0507 Big Sandy-Guyandotte 0508 Great Miami 0509 Middle Ohio 0510 Kentucky-Licking 0511 Green 0512 Wabash 0513 Cumberland 0514 Lower Ohio 06 Tennessee Region 0601 Upper Tennessee 0602 Middle Tennessee-Hiwassee 0603 Middle Tennessee-Elk 0604 Lower Tennessee 07 Upper Mississippi Region 0701 Mississippi Headwaters 0702 Minnesota 0703 St. Croix 0704 Upper Mississippi-Black-Root 0705 Chippewa 0706 Upper Mississippi-Maquoketa-Plum 0707 Wisconsin 0708 Upper Mississippi-Iowa-Skunk-Wapsipinicon 0709 Rock 0710 Des Moines 0711 Upper Mississippi-Salt 0712 Upper Illinois 0713 Lower Illinois 0714 Upper Mississippi-Kaskaskia-Meramec 08 Lower Mississippi Region 0801 Lower Mississippi-Hatchie 0802 Lower Mississippi-St. Francis 0803 Lower Mississippi-Yazoo 0804 Lower Red-Ouachita 0805 Boeuf-Tensas 0806 Lower Mississippi-Big Black 0807 Lower Mississippi-Lake Maurepas 0808 Louisiana Coastal 0809 Lower Mississippi 09 Souris-Red-Rainy Region 0901 Souris 0902 Red 0903 Rainy 10 Missouri Region 1001 Saskatchewan 1002 Missouri Headwaters 1003 Missouri-Marias 1004 Missouri-Musselshell 1005 Milk 1006 Missouri-Poplar 1007 Upper Yellowstone 1008 Big Horn 1009 Powder-Tongue 1010 Lower Yellowstone 1011 Missouri-Little Missouri 1012 Cheyenne 1013 Missouri-Oahe 1014 Missouri-White 1015 Niobrara 1016 James 1017 Missouri-Big Sioux 1018 North Platte 1019 South Platte 1020 Platte 1021 Loup 1022 Elkhorn 1023 Missouri-Little Sioux 1024 Missouri-Nishnabotna 1025 Republican 1026 Smoky Hill 1027 Kansas 1028 Chariton-Grand 1029 Gasconade-Osage 1030 Lower Missouri 11 Arkansas-White-Red Region 1101 Upper White 1102 Upper Arkansas 1103 Middel Arkansas 1104 Upper Cimarron 1105 Lower Cimarron 1106 Arkansas-Keystone 1107 Neosho-Verdigris 1108 Upper Canadian 1109 Lower Canadian 1110 North Canadian 1111 Lower Arkansas 1112 Red Headwaters 1113 Red-Washita 1114 Red-Sulphur 12 Texas-Gulf Region 1201 Sabine 1202 Neches 1203 Trinity 1204 Galveston Bay-San Jacinto 1205 Brazos Headwaters 1206 Middle Brazos 1207 Lower Brazos 1208 Upper Colorado 1209 Lower Colorado-San Bernard Coastal 1210 Central Texas Coastal 1211 Nueces-Southwestern Texas Coastal 13 Rio Grande Region 1301 Rio Grande Headwaters 1302 Rio Grande-Elephant Butte 1303 Rio Grande-Mimbres 1304 Rio Grande-Amistad 1305 Rio Grande Closed Basins 1306 Upper Pecos 1307 Lower Pecos 1308 Rio Grande-Falcon 1309 Lower Rio Grande 14 Upper Colorado Region 1401 Colorado Headwaters 1402 Gunnison 1403 Upper Colorado-Dolores 1404 Great Divide-Upper Green 1405 White-Yampa 1406 Lower Green 1407 Upper Colorado-Dirty Devil 1408 San Juan 15 Lower Colorado Region 1501 Lower Colorado-Lake Mead 1502 Little Colorado 1503 Lower Colorado 1504 Upper Gila 1505 Middle Gila 1506 Salt 1507 Lower Gila 1508 Sonora 16 Great Basin Region 1601 Bear 1602 Great Salt Lake 1603 Escalante Desert-Sevier Lake 1604 Black Rock Desert-Humboldt 1605 Central Lahontan 1606 Central Nevada Desert Basins 17 Pacific Northwest Region 1701 Kootenai-Pend Oreille-Spokane 1702 Upper Columbia 1703 Yakima 1704 Upper Snake 1705 Middle Snake 1706 Lower Snake 1707 Middle Columbia 1708 Lower Columbia 1709 Willamette 1710 Oregon-Washington Coastal 1711 Puget Sound 1712 Oregon Closed Basins 18 California Region 1801 Klamath-Northern California Coastal 1802 Sacramento 1803 Tulare-Buena Vista Lakes 1804 San Joaquin 1805 San Francisco Bay 1806 Central California Coastal 1807 Southern California Coastal 1808 North Lahontan 1809 Northern Mojave-Mono Lake 1810 Southern Mojave-Salton Sea 19 Alaska Region 1901 Arctic Slope 1902 Northwest Alaska 1903 Yukon 1904 Southwest Alaska 1905 South Central Alaska 1906 Southeast Alaska 20 Hawaii Region 2001 Hawaii 2002 Maui 2003 Kahoolawe 2004 Lanai 2005 Molokai 2006 Oahu 2007 Kauai 2008 Niihau 2009 Northwestern Hawaiian Islands 2010 Other Pacific Islands 21 Caribbean Region 2101 Puerto Rico 2102 Virgin Islands 2103 Caribbean Outlying Areas