are mostly located around the Pacific Ocean, but are also found in the eastern Indian Ocean, with a few shorter convergent margin segments in other parts of the Indian Ocean, in the Atlantic Ocean, and in the Mediterranean. They are found on the oceanward side of island arcs and Andean-type orogens. Globally, there are over 50 major ocean trenches covering an area of 1.9 million km² or about 0.5% of the oceans.

Trenches are geomorphologically distinct