Niagara Falls is the collective name for three waterfalls that straddle the international border between the Canadian province of Ontario and the American state of New York. They form the southern end of the Niagara Gorge. The Horseshoe Falls drop about 188 feet (57 m), while the height of the American Falls varies between 70 and 100 feet (21 and 30 m) because of the presence of giant boulders at its base. The larger Horseshoe Falls are about 2,600 feet (790 m) wide, while the American Falls are 1,060 feet (320 m) wide. The distance between the American extremity of the Niagara Falls and the Canadian extremity is 3,409 feet (1,039 m).