About 12,000 years ago, Niagara Falls was 11 kilometres (7 miles) downstream from its present position. Until the early 1950s, the Falls eroded at the average rate of one metre (3 feet) per year.

Since then, major water diversions have spread out the flow more evenly, slowing the rate of erosion at the Falls. These include the Sir Adam Beck #2 Generating Station (1954) on the Canadian side of the border, the Robert Moses Niagara Power Plant (1961) on the American side of the Niagara River, and the International Control Works (1954-1963).

It is suggested that now the rate of erosion could be as low as 30 centimetres (one foot) every ten years.

• The Niagara River is about 56 kilometres (35 miles) long and is the natural outlet from Lake Erie to Lake Ontario. It is one of the world's greatest sources of hydroelectric power.
• The elevation between the two lakes is about 99 metres (326), with the half-way point occurring at the Falls.
• The total area drained by the Niagara River is approximately 684,000 square kilometres (264,000 square miles).
• The average fall from Lake Erie to the beginning of the Upper Niagara Rapids is only 2.7 metres (9 feet)

• The Canadian Horseshoe Falls, for the most part, fall 52 metres (170 feet) into the Maid of the Mist Pool.
• At the American Falls, the water plunges vertically, ranging from 21 to 34 metres (70 to 110 feet), to the rock at the base of the Falls.
• The Niagara Gorge extends from the Falls for 11 kilometres (7 miles) downstream to the foot of the escarpment at Queenston.
• More than 168,000 cubic metres (6 million cubic feet) of water go over the crestline of the Falls every minute during peak daytime tourist hours. It is difficult to determine the depth of the water at the crestline due to various flows and conditions of the river.