The Deepest Known Point in the Ocean Is Nearly 11 Kilometers Down

The ocean floor is far from flat, and its lowest known point lies in the western Pacific. NOAA’s National Ocean Service identifies it as the Challenger Deep, located at the southern end of the Mariana Trench, several hundred kilometers southwest of Guam. NOAA gives its depth as approximately 10,935 meters, or 35,876 feet. For comparison, the same NOAA page puts the average depth of the ocean at about 3,682 meters, or 12,080 feet. The Challenger Deep is therefore roughly three times deeper than the ocean is on average. The word approximately is deliberate. Measuring a point that far below the surface is difficult, so the figure is given as an estimate and not as an exact number.