Niagara County is in the U.S. state of New York. As of the 2020 United States census, the population was 212,666. The county seat is Lockport. The county name is from the Iroquois word Onguiaahra; meaning the strait or thunder of waters. The county is part of the Western New York region of the state.
Niagara County is part of the Buffalo–Niagara Falls metropolitan area, and across the Canada–US border is the province of Ontario.