Niagara Falls (French: les Chutes du Niagara) are massive waterfalls on the Niagara River, straddling the international border separating the Canadian province of Ontario and the U.S. state of New York. The falls are 17 miles (27 km) north-northwest of Buffalo, New York, 75 miles (120 km) south-southeast of Toronto, Ontario, between the twin cities of Niagara Falls, Ontario, and Niagara Falls, New York.

Niagara Falls is composed of two major sections separated by Goat Island: Horseshoe Falls, on the Canadian side of the border and American Falls on the United States side. The smaller Bridal Veil Falls also is located on the American side, separated from the main falls by Luna Island. Niagara Falls were formed when glaciers receded at the end of the Wisconsin glaciation (the last ice age), and water from the newly-formed Great Lakes carved a path through the Niagara Escarpment en route to the Atlantic Ocean. While not exceptionally high, the Niagara Falls are very wide. More than six million cubic feet (168,000 m³) of water falls over the crest line every minute in high flow, and almost 4 million cubic feet (110,000 m³) on average. It is the most powerful waterfall in North America.

The Niagara Falls are renowned both for their beauty and as a valuable source of hydroelectric power. Managing the balance between recreational, commercial, and industrial uses has been a challenge for the stewards of the falls since the 1800s.

Straddling the Canadian-United States International Border and both in the Province of Ontario and the State of New York, Niagara Falls attracts some 12 Million tourists to her majestic awesome beauty each year.

The Niagara is a fairly young river, only 12,000 years old!, a microsecond in geological time. The Niagara Escarpment, which was created by erosion is much older. The glaciers pressed down on the land during the last ice age and laid down layers of sediment, then the slow process of erosion of ice and water ate at the surface of the escarpment.

The mighty river plunges over a cliff of dolostone and shale. Niagara Falls is the second largest falls on the globe next to Victoria Falls in southern Africa.

One fifth of all the fresh water in the world lies in the four Upper Great Lakes-Michigan, Huron, Superior and Erie. All the outflow empties into the Niagara river and eventually cascades over the falls.

At the bottom of the falls, the water travels 15 miles over many gorges until it reaches the fifth Great Lake-Ontario. The land between the lakes does not slope at an even grade, but forms a spectacular drop approximately the same height as a 20 story building and this is known as the "Niagara Escarpment" Two billion years ago it was buried under a blanket of ice. As the years past, the process of erosion took place, (and still does) five distinct 'gorges' were formed-Lewiston Brange Gorge, Old Narrow Gorge, Upper & Lower Great Gorges and the Whirlpool Narrow Gorge.

Approximately 500 years ago the river encountered an obstacle that caused it to 'split into two channels', thus Goat Island was formed named after John Stedman whose goat herds froze to death in the winter of 1780). This was the original sediment left from a vanished Lake Tonawanda (an Indian name).

On the eastern part of the island, the American Falls took shape, the Horseshoe Falls, is on the western side, where the river angles some 90 degrees.

The water flow on the American side of the falls is much less in strength because of Goat Island, whereas Horseshoe Falls has no obstruction to divert it.

It should be noted that a third much narrower falls exists. Over the years these falls have been called at different times; Luna Falls, Iris Falls and is currently named Bridal Veil Falls.

Man has not been able to completely control the flow of the water over the falls, even modern engineers have tried. Much of the water today is fed through underground channels and pipes to nearby hydro electric power stations.