Let's acknowledge up front that Hawaii boasts the country's tallest waterfalls (Olo'upena, Pu'uka'oku, and Waihilau, according to the fascinating World Waterfall Database) and among the globe's most stunning; and that Alaska claims its own spectacular (and often super-remote) falls, including Brooks Falls in Katmai ...

The answer depends on whether you measure by height or volume. Hawaii holds the title for the tallest waterfall in the U.S. with Olo'upena Falls on Molokai, which drops a staggering 2,953 feet. For the contiguous United States, Washington is home to the highest, Colonial Creek Falls, at 2,568 feet. However, if you define "biggest" by volume of water, New York wins definitively with Niagara Falls. While it only drops about 167 feet, it moves an average of 85,000 cubic feet of water per second, making it the most powerful waterfall in North America. In 2026, these sites remain major environmental landmarks, though the Hawaiian falls are often seasonal and only visible via helicopter, whereas Niagara is a massive, year-round industrial and tourist powerhouse.