Robert Angus Smith (1817-1884) describes acid rain.

The State of New York establishes a 715,000 acre Forest Preserve in the Adirondack Mountains with the stipulation that it "shall be kept forever as wild forest lands." (May 15)

Yosemite National Park established in California. (October 1)

U.S. Census Department announces the Frontier boundary, beyond which there were no more than two settlers per square mile.

Twenty-seven committed environmentalists form the Sierra Club dedicated to "exploring, enjoying, and rendering accessible the mountain the mountain regions of the Pacific Coast." Charter members included John Muir and Joseph LeConte, among others. (May 28)

Animal Rights Considered in Relation to Social Progress by Henry S. Salt released.

"Progressive" Environmentalism gains popularity, espousing governmental intervention in the public interest to offset exploitation of natural resources by private developers.

U.S. Rivers and Harbors Act bans pollution of navigable waters.

The United States Forest Service is established within the Department of Agriculture to manage forest reserves.

National Audubon Society founded.

U.S. President Theodore Roosevelt hosts first Governors' Conference on Conservation and creates the National Conservation Commission to inventory America's natural resources.

Chlorination is first used extensively at U.S. water treatment plants, producing water 10 times purer than when filtered.

The Weeks Act appropriates $9 million dollars to purchase 6 million acres of land in the eastern United States for the purpose of establishing national forests.

Martha, the last passenger pigeon, dies in the Cincinnati zoo, becoming a symbol for crusades against species extinction. (September 1)

Hunting of migratory bird species is restricted by treaty between U.S. and Canada.

Izaak Walton League established as non-profit research and advocacy organzation.

First National Conference on Outdoor Recreation held.

The International Union of Biological Sciences establishes the International Office for the Protection of Nature, based in Brussels, Belgium. (July 10)

Civilian Conservation Corps employs over two million Americans in forestry, flood control, soil erosion, and beautification projects in an attempt to boost the economy while addressing the needs of the land.

U.S. Taylor Grazing Act regulates grazing on federal lands.

Effigy Mounds National Monument established in Iowa. (October 25)

Aldo Leopold's seminal book A Sand County Almanac published.

International Technical Conference on the Conservation of Living Resources. (April 18)

The Multiple Use and Sustained Yield Act redefined the purpose of the national forests to include not only timber and watershed concerns, but also recreation, wildlife, fishing, hunting, and soil concerns.

United Nations Conference on New Sources of Energy, Rome, Italy. (August 21-31)

Hawaii Volcanoes National Park established in Hawaii. (September 22)

First World Conference on National Parks, Seattle, Washington. (June 30-July 7)

Padre Island National Seashore established in Texas. (September 28)

Petrified Forest National Park established in Arizona. (December 9)

Conference on Application of Science and Technology for the benefit of the Less Developed Areas, Geneva, Switzerland. (February 4-20)

U.S. Congress passes the first comprehensive legislation for clean air, with an allocation of $95 million. (December 17)

Canyonlands National Park established in Utah. (September 12)

The Land & Water Conservation Fund Act is established to purchase park and refuge lands with royalties from offshore oil drilling.

Congress passes Water Quality Act, giving federal government power to set water standards in absence of slate action.

Congress passes the Solid Waste Disposal Act, its first major solid waste legislation.

Guadalupe Mountains National Park established in Texas. (October 15)

The bald eagle, California condor, whooping crane, gray wolf, and grizzly bear are placed on the Endangered Species List. (March 11)

U.S. Congress passes the Air Quality Act, allocating $25 million to air quality protection efforts. (November 21)

First United Nations Conference on the Exploration and Peaceful Uses of Outer Space, Vienna, Austria. (August 14-27)

U.S. President Lyndon Johnson signs the Central Arizona project into law, protecting the Colorado River -- which flows through the Grand Canyon -- from damming. (September 30)

North Cascades National Park established in Washington State. (October 2)

Redwoods National Park established in California. (October 2)

U.S. President Lyndon Johnson signs a bill establishing the National Wild and Scenic Rivers System, creating a legislative category of protection which Congress could apply to any free-flowing river in the country. (October 2)

Biscayne National Park established in Florida. (October 18)

United Nations General Assembly Resolution 2398 on the Problems of Human Environment, initiating subsequent Stockholm Conference on the Human Environment. (December 3)

First landing on moon, U.S. Apollo XI. (July 20)

U.S. Senator Gaylord Nelson calls for national teach-in on the environment to be called "Earth Day".

An estimated 20 million people participate in the first Earth Day demonstrations and activities across the country.

National Environmental Policy Act (NEPA) signed into law. Requires an analysis of the environmental impacts of federal actions.

Clean Air Act signed into law.

President's Council on Environmental Quality established. CEQ advises and assists the President on environmental policies; oversees federal agencies implementation of the environmental impact assessment process.

Eight species of whales -- Blue, Bowhead, Finback, Gray, Humpback, Right, Sei, and Sperm -- are placed on the Endangered Species List. (June 2)

U.S. Environmental Protection Agency (EPA) begins operations. (October 2). William D. Ruckelshaus appointed first Administrator.

American and peregrine falcons are placed on the Endangered Species List. (October 13)

Technical Conference on Marine Pollution and Its Effects on Living Resources and Fishing, sponsored by the Food & Agriculture Organization, Rome, Italy. (December 9-18)

Natural Resources Defense Council (NRDC) founded to protect the environment and human health through advocacy, litigation, scientific research and education.

U.S. government approves the Alaska Native Claims Settlement Act. (December 18)

Congress passes Clean Water Act, forbidding discharges of pollutants into navigable waters.

Oregon passes the nations first bottle recycling law.

United Nations Conference on the Human Environment, Stockholm, Sweden. (June 5-16)

U.S. Environmental Protection Agency (EPA) bars registration and interstate sales of DDT because of its persistence in the environment and accumulation in the food chain. (June 14)

Second World Conference on National Parks, Yellowstone National Park, Wyoming. (September 18)

Establishment of the United Nations Environment Programme (UNEP) by the UN General Assembly. (December 15)

U.S. Congress passes the Endangered Species Act, referred to as the "most comprehensive legislation for the protection of endangered species ever enacted by any nation." (December 28)

Russell E. Train appointed Administrator of U.S. Environmental Protection Agency (EPA).

World Population Conference, Bucharest, Romania. (August 19-30)

World Food Conference, Rome, Italy. (November 5-16)

Forest and Rangeland Renewable Resources Planning Act establishes planning process for all forest and rangeland resources.

Belgrade Charter: Global Framework for Environmental Education. (October 28)

National Forest Management Act (NFMA) Requires the U.S. Forest Service to include economic, wildlife, wilderness and recreational uses in planning.

Federal Lands Policy and Management Act (FLPMA) Governs the use of the national lands managed by the Bureau of Land Management.

Douglas M. Costle appointed Administrator of U.S. Environmental Protection Agency (EPA).

Omnibus Parks Act adds Santa Monica Mountains, Golden Gateway, and Golden Gate National Recreation Areas to the National Park System.

Formation of EarthFirst! and radical environmental movement, inspired by Edward Abbey's book The Monkeywrench Gang.

World Climate Conference, Geneva, Switzerland. (February 23)

U.S. President Jimmy Carter signs into law the Alaska National Interest Lands Conservation Act, protecting 104 million acres of federal land -- including Denali, Gates of the Arctic, Glacier Bay, Katmai, Lake Clark, and Wrangell-St. Elias National Parks and Preserves. (December 2)

World National Parks Congress, Denpasar, Bali, Indonesia. (October 11-22)

World Charter for Nature adopted by the UN General Assembly. (October 28)

William D. Ruckelshaus appointed Administrator of U.S. Environmental Protection Agency (EPA) for the second time.

International Society for Environmental Education (ISEE) and World Council for Biosphere established, New Delhi, India. (February 29)

British scientists discover that a "hole" in the ozone layer develops over Antarctica each winter.

The U.S. sets up a Conservation Reserve Program to remove environmentally sensitive farmland from agricultural use.

Lee M. Thomas appointed Administrator of U.S. Environmental Protection Agency (EPA).

U.S. Congress passes reauthorization and expansion of the Clean Water Act over veto by President Reagan.

The Rainforest Alliance is created and incorporated as a non-profit, based in New York City.

UN General Assembly Resolution on Protection of Global Climate for Present and Future Generations of Mankind. (December 6)

Thirteen industrial nations agree to halt production of CFCs by the year 2000.

Hague Declaration on the Environment. (March 11)

Declaration of Brazilia on the Environment, Latin American-Caribbean environmental summit. (March 31)

Helsinki Declaration on Protection of the Ozone Layer signed. (May 2)

UNEP Decision on Global Climate Change, Nairobi, Kenya. (May 25)

William K. Reilly appointed Administrator of U.S. Environmental Protection Agency (EPA).

A Georgia wilderness bill adds 24,200 acres of national forest lands to the National Wilderness Preservation System.

Dry Tortuga National Park established in Florida. (October 26)

California wilderness bill adds 400,450 acres of national forest lands to National Wilderness Preservation System.

Carol M. Browner appointed Administrator of U.S. Environmental Protection Agency (EPA).

U.S. Congress passes the California Desert Protection Act, establishing Death Valley and Joshua Tree National Parks as well as the Mojave National Preserve in California, bringing the National Wilderness Preservation System up to 104.7 million acres, which totals more than four percent of the total U.S. land base.

Sen. Gaylord Nelson,the founder of Earth Day in 1970, is awarded the Presidential Medal of Freedom by President Bill Clinton.

Mojave National Park established in California.

U.S. Congress passes the Omnibus Parks Act establishing the Tallgrass Prairie National Preserve in Kansas and the Opal Creek Wilderness in Oregon.

U.S. President Bill Clinton establishes Grand Staircase-Escalante National Monument in Utah.

U.S. Congress designated nearly 6 million acres of wilderness, mostly in Alaska's Noatak Wilderness Area.

Representatives from more than 150 countries meet in Kyoto, Japan, where they agree to reduce emissions of greenhouse gases 5.2 percent worldwide by 2010.

U.S. Congress passes law, the National Wildlife Refuge Improvement Act, increasing protection in national wildlife refuges.

The U.S. National Park Service and Department of Transportation sign an agreement to work together to significantly reduce traffic in Grand Canyon, Yosemite, and Zion National Parks.

U.S. Congress appropriates money from the Land and Water Conservation Fund to protect Yellowstone, Headwaters Forest, and the Everglades, and provides funding for acquisition of important natural and recreation areas in 38 other states.

New US Environmental Protection Agency website provides public access to local pollution data throughout the United States.

Otay Mountain Wilderness, east of San Diego, adds 15,000 acres to the National Wilderness Preservation System.

The Opal Creek Wilderness Area in Oregon, at 20,724 acres, is designated by Congress.

Black Canyon of the Gunnison National Monument, Colorado is made a National Park. Redesignation addes 22,000 acres of park Wilderness and 4,700 acres of BLM Wilderness to the National Wilderness Preservation System.

U.S. President Clinton issues his directive to the USFS to conduct an EIS leading to possible long-term protection of 50-60 million acres of roadless lands.

The Dugger Mountain Wilderness Act designates 9,200 acres in the Talladega National Forest, 70 miles east of Birmingham, AL.

US Environmental Protection Agency proposes comprehensive plan to clean up Hudson River PCBs.

Former New Jersey Governor Christine Todd Whitman appointed Administrator of U.S. Environmental Protection Agency (EPA).

United States joins 90 other nations in signing the international Convention on Persistent Organic Pollutants.