What is the deepest named point in Earth's oceans?

The deepest named point in Earth’s oceans is Challenger Deep.

Challenger Deep lies within the Mariana Trench in the western Pacific Ocean. It is a series of deep basins rather than a perfectly uniform single hole, and modern surveys place its deepest areas at roughly 10.9 kilometers below mean sea level. Exact figures vary because sonar readings, pressure measurements, sound-speed corrections, and the precise location of the deepest spot all introduce uncertainty.

The feature was first sounded by the 1872–1876 Challenger expedition, the first major scientific voyage devoted entirely to oceanography. On 23 March 1875, HMS Challenger recorded a depth of 4,475 fathoms, about 8,184 meters, at a site later associated with the trench’s extreme depth. The bathymetric name honors that expedition. Later milestones include the 1960 Trieste descent, James Cameron’s solo dive in 2012, and repeated full-ocean-depth dives by modern submersibles. Calypso, Milwaukee, and Horizon are names for other deep features, not the oceanic record-holder.