Which ocean contains the Mariana Trench?

The Mariana Trench lies in the Pacific Ocean.

The Mariana Trench is a crescent-shaped depression in the western Pacific, east of the Mariana Islands. Its deepest known point, Challenger Deep, reaches roughly 10,900 metres below sea level, although measurements vary as instruments and surveying methods improve. It is the deepest known point in Earth’s oceans.

The trench formed at a subduction zone where the Pacific Plate moves beneath the smaller Mariana Plate. Extreme pressure, darkness, and cold make the environment difficult to explore, but scientists have found specialized organisms adapted to these conditions.

The first crewed descent to Challenger Deep took place in 1960, when Jacques Piccard and U.S. Navy lieutenant Don Walsh reached the bottom in the bathyscaphe Trieste. Film director James Cameron made a solo descent in 2012. Robotic vehicles and later crewed missions have continued to study the trench, revealing that even the deepest ocean floor contains active biological and geological processes.