Is it Niagra Falls, or Niagara Falls?

While browsing Blogger/BlogSpot website, Tunay na Lalake (Real Man), the blog mentions Lyoto Machida. I check his name on Wikipedia. At the time I was on the bottom of the article about him, I clicked Rashad Evans’s name. And then, I click on Niagara Falls, New York.

I don’t know that Niagara Falls was in New York. All I know is that Niagara Fall was in Canada.

And also, I thought that spelling was Niagara Falls, until it was Niagara Falls.

I learned all these information from Wikipedia.