The Niagara River flows to the north from Lake Erie to Lake Ontario. It serves as part of the border between the Province of Ontario in Canada and New York State in the United States. There are various theories as to the origin of the name. According to NASA, "Niagara" comes from a Native American word meaning "at the neck". According to George R. Stewart, it comes from the name of an Iroquois town called "Ongniaahra", meaning "point of land cut in two".

The river, which is occasionally described as a "strait", is approximately 56 kilometres (35 mi) long and includes Niagara Falls along its course. The falls have moved upstream from the Niagara Escarpment about 11 kilometers (7 mi) in the last 12,000 years, resulting in a gorge below the falls. Today, diversion of the river for electricity generation has significantly reduced the rate of erosion.

Power plants on the river are the Sir Adam Beck Hydroelectric Power Stations, on the Canadian side, and the Robert Moses Niagara Power Plant, built in 1961, on the American side. The sites generate 4.4 gigawatts of electricity combined. The river flow is also regulated by the International Control Works built in 1954. Shipping on the Great Lakes bypasses the Niagara River and Niagara Falls using the Welland Canal, part of the Saint Lawrence Seaway, located on the Canadian side.

The total drop in elevation along the river is 326 ft (99 meters). The Niagara Gorge extends 7 mi (11.26 km)downstream from the Falls and includes the Niagara Whirlpool and another section of rapids. It also one of the few rivers in North America to flow northward, and empties 2/5ths of the fresh water in North America.

The Niagara River features two large islands, Grand Island and Goat Island, both in the United States. The western end of the Erie Canal is near Grand Island. Goat Island and the tiny Luna Island split Niagara Falls into its three sections, the Horseshoe, Bridal Veil, and American Falls. Navy Island, on the Canadian side, is near the north end of Grand Island, while Strawberry Island and Motor Island lie southeast of Grand Island. Squaw Island lies further upstream, alongside the city of Buffalo.

The Niagara River and its tributaries, Tonawanda Creek and the Welland River, formed part of the last section of the Erie Canal and Welland Canal. After leaving Lockport, New York, the Erie Canal proceeds southwest until it enters Tonawanda Creek. After entering the Niagara River, watercraft then proceed southward to the final lock, where a short section of the canal allows boats to avoid the turbulent shoal water at the river intake and enter Lake Erie.

The Welland Canals used the Welland River as a connection to the Niagara River south of the falls, allowing water traffic to safely re-enter the Niagara River and proceed to Lake Erie.

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 during 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.

The river was an important route to liberation before the American Civil War, when many African-Americans escaping slavery on the Underground Railroad crossed it to find freedom in Canada.

On the Canadian side of the river the Niagara Parks Commission maintains all of the shoreline property, except the sites of Fort George and Fort Erie, as a public greenspace and environmental heritage.

Today, the river is the namesake of Niagara Herald Extraordinary at the Canadian Heraldic Authority.

From: en.wikipedia.org/wiki/Niagara_river