The Niagara River flows to the north from Lake Erie to Lake Ontario. It serves as the border between the province of Ontario in Canada and New York state in the United States.
The river is about 56 kilometres (35 miles) long and includes Niagara Falls along its course. The falls is thought to have moved upstream 11 kilometers (7 miles) in the last 12,000 years but modern diversion of the river for power generation has reduced the erosion to a minuscule amount. Power plants on the river are the Adam Beck Generating Station built in 1954, on the Canadian side, and the Robert Moses Niagara Power Plant, built in 1961, on the American side. The sites power 4.4 gigawatts of electrical generation. The river flow is also regulated by the International Control Works built in 1954. Shipping on the Great Lakes bypasses the Niagara River and Falls on the Welland Canal.
The total drop in elevation along the river is 99 meters (326 feet). The Upper Niagara Rapids drop 50 feet in a half mile before the Falls. The Niagara Gorge extends seven miles downstream of the Falls and includes the Niagara Whirlpool and another section of rapids.
The Niagara River features two large islands: Grand Island and Goat Island. The western end of the Erie Canal is near Grand Island. Goat Island spilts Niagara Falls into the American and Horseshoe Falls.
Three international bridges cross the river: the Peace Bridge at Buffalo, the Rainbow Bridge at Niagara Falls and the Niagara River Bridge between Lewiston and Queenston. Two bridges link Grand Island with both shores and the American Rapids Bridge links Goat Island to the American shore.
Cities on the Niagara River include:
Several battles occurred along the Niagara River which was historically defended by Fort George (Canadian side) and Fort Niagara (American side) at the mouth of the river and Fort Erie (Canadian side) at the head of the river. These forts were important in the French and Indian War and the American Revolutionary War. The Battle of Queenston Heights took place near the river in the War of 1812.