New York State Route 266 (NY 266) is a state highway in Erie County, New York, in the United States. It runs along the Niagara River from the city of Buffalo to the city of Tonawanda. The southern terminus of the route is at the ramps leading to Interstate 190 (I-190) exit 8 in Buffalo. Its northern terminus is at an intersection with NY 265 just south of North Tonawanda in Tonawanda.

The Niagara River is a river that flows north from Lake Erie to Lake Ontario. It forms part of the border between the province of Ontario in Canada and the state of New York in the United States. There are differing theories as to the origin of the river's name. According to Iroquoian scholar Bruce Trigger, Niagara is derived from the name given to a branch of the locally residing native Neutral Confederacy, who are described as being called the Niagagarega people on several late-17th-century French maps of the area. According to George R. Stewart, it comes from the name of an Iroquois town called Ongniaahra, meaning "point of land cut in two".