The American Falls is one of three waterfall

Waterfall

A waterfall is a place where flowing water rapidly drops in elevation as it flows over a steep region or a cliff.-Formation:Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens...

s that together are known as Niagara Falls

Niagara Falls

The Niagara Falls, located on the Niagara River draining Lake Erie into Lake Ontario, is the collective name for the Horseshoe Falls and the adjacent American Falls along with the comparatively small Bridal Veil Falls, which combined form the highest flow rate of any waterfalls in the world and has...

 on the Niagara River

Niagara River

The Niagara River flows north from Lake Erie to Lake Ontario. It forms part of the border between the Province of Ontario in Canada and New York State in the United States. There are differing theories as to the origin of the name of the river...

 along the Canada-U.S. border. Unlike the much larger Horseshoe Falls

Horseshoe Falls

The Horseshoe Falls, also known as the Canadian Falls, is part of Niagara Falls, on the Niagara River. Approximately 90% of the Niagara River, after diversions for hydropower generation, flows over Horseshoe Falls. The remaining 10% flows over the American Falls...

, of which two-thirds of the falls is located in Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 and one-third in New York State, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the American Falls is completely within the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

.
The falls receive approximately 10% of the flow from Niagara River, with most of the rest going over Horseshoe Falls, from which it is separated by Goat Island

Goat Island (New York)

Goat Island is a small island in the Niagara River, located in the middle of Niagara Falls between the Bridal Veil Falls and the Horseshoe Falls...

.