Can all falling water be considered a waterfall? Not exactly. To be deemed a waterfall a segment must be at least five feet high. To further qualify, according to Milestone Press, the waterfall must come from a river, creek, or stream that provides water at least annually.

The height of a waterfall is defined as the total vertical drop from the point where the water begins its descent (the crest) to the pool or surface below (the base). In 2026, the world’s tallest uninterrupted waterfall remains Angel Falls in Venezuela, with a staggering total height of 979 meters (3,212 feet) and a single clear drop of 807 meters. For comparison, the iconic Niagara Falls is relatively short but high in volume, standing at only about 51 meters (167 feet). Geologically, height is just one metric; waterfalls are also categorized by their "leap," "cascade," or "horsetail" style. The height is often measured using a clinometer or laser rangefinder to account for the spray and the varying levels of the plunge pool. Understanding the height is critical for safety, as even a 10-meter fall creates enough hydraulic force to be life-threatening. Interestingly, the largest waterfall in the world by height is actually underwater: the Denmark Strait cataract, which falls over 3,500 meters beneath the Atlantic Ocean.