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".