United States 6,777
Colorado 981
California 363
New York (State) 177
Washington (State) 141
Texas 134
Florida 125
China 123
Great Lakes (North America) 123
Pennsylvania 119
Europe 110
New Jersey 109
Massachusetts 104
Canada 99
Idaho 99
Ohio 92
Alaska 91
Michigan 88
Minnesota 79
Denver Metropolitan Area 78
European Union countries 70
Illinois 70
Great Britain 69
Wisconsin 66
Nevada 63
Wyoming 63
Montana 61
Tennessee 61
Missouri 58
North Carolina 58
Arizona 57
Kansas 56
Maryland 56
Chesapeake Bay (Md. and Va.) 54
Utah 54
Alabama 53
Mexico, Gulf of 53
India 50
North America 50
West (U.S.) 50
Virginia 48
Mexico 47
Indiana 45
Oklahoma 44
Denver 43
Developing countries 43
Oregon 41
Japan 40
Louisiana 40
South Carolina 40
Georgia 39
Iowa 36
New Mexico 36
West Virginia 36
Connecticut 35
Great Lakes Region (North America) 34
Idaho National Laboratory Region 34
Kentucky 34
Arctic regions 31
European Economic Community countries 31
Jefferson County 31
Michigan, Lake 31
Washington (D.C.) 31
New York 30
Chesapeake Bay Watershed 29
Los Angeles 29
Mississippi 29
Asia 27
England 27
Europe, Eastern 27
Middle West 27
Mississippi River 27
Nebraska 26
Erie, Lake 25
Rhode Island 25
San Joaquin Valley 25
New England 24
North Dakota 24
Maine 23
Snake River Plain (Idaho and Or.) 23
South Dakota 23
Soviet Union 22
Front Range (Colo. and Wyo.) 21
Germany 21
Hawaii 21
Atlantic Ocean 20
Australia 20
Cape Cod 20
Great Lakes 20
Ontario 20
Hudson River (N.Y. and N.J.) 19
Mississippi River Watershed 19
Puget Sound 19
Delaware 18
Superior, Lake 18
Animas River Watershed (Colo. and N.M.) 17
Long Island 17
Long Island Sound (N.Y. and Conn.) 17
New Hampshire 17
Southeast Asia 17