Milwaukee Deep Milwaukee Deep Milwaukee Deep, also known as The Milwaukee Depth, () is the deepest part of the Atlantic Ocean and is part of the Puerto Rico Trench. It has a maximum depth of at least . It is just north of the coast of Puerto Rico at "Punto Palmas Altas" in Manatí. This ocean floor feature is named for the USS "Milwaukee" (CL-5), a U.S. Navy Omaha class cruiser, which discovered the Milwaukee Deep on February 14, 1939 with a reading of . On August 19, 1952, the U.S. Fish and Wildlife vessel "Theodore N. Gill" obtained a reading of
Ocean hadalpelagic. This lies between and is the deepest oceanic zone. The benthic zones are aphotic and correspond to the three deepest zones of the deep-sea. The bathyal zone covers the continental slope down to about . The abyssal zone covers the abyssal plains between 4,000 and 6,000 m. Lastly, the hadal zone corresponds to the hadalpelagic zone, which is found in oceanic trenches. The pelagic zone can be further subdivided into two subregions: the neritic zone and the oceanic zone. The neritic zone encompasses the water mass directly above the continental shelves whereas the oceanic zone includes all the completely