Niagara County is a county located in the U.S. state of New York. As of the 2010 census, the population was 216,469. The county seat is Lockport. The county name is from the Iroquois word Onguiaahra; meaning the strait or thunder of waters.\Niagara County is part of the Buffalo-Niagara Falls metropolitan area, and its Canadian border is the province of Ontario.It is the location of Niagara Falls and Fort Niagara, and has many parks and lake shore recreation communities.