Milwaukee Deep, also known as the Milwaukee Depth, is part of the Puerto Rico Trench. Together with the surrounding area, known as Brownson Deep, the Milwaukee Deep forms an elongated depression that constitutes the floor of the trench. As there is no geomorphological distinction between the two, it has been proposed that the use of both names to refer to distinct areas should be reviewed. The floor of the Puerto Rico Trench constitutes the deepest point in the Atlantic Ocean. During the Five Deeps Expedition, explorer Victor Vescovo achieved the first manned descent to this location. Media outlets overwhelmingly referred to the area as the Brownson Deep, while the name Milwaukee Deep was used by others. However, likely due to the factors mentioned above, the expedition has not used any particular name to refer to the site of their Atlantic dive. The Puerto Rico Trench has a maximum depth of no more than, as measured to be the deepest point in the Atlantic Ocean by Vescovo during his descent. Previously, however, the depth of the Milwaukee Deep had been reported by various sources as,, or. It is just north of the coast of Puerto Rico at Punto Palmas Altas in Manatí.
History
The ocean floor feature is named for the USS Milwaukee, 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 at, virtually identical with the Milwaukees reading. By then, the existence of deep water to the Atlantic Ocean side of the Caribbean had been known for more than a century. One of the area's earliest soundings was obtained June 12, 1852 by Lt. S. P. Lee, U.S. Navy brigDolphin, with a reading of at. In 1964, the French submersible Archimede explored the Puerto Rico Trench to a depth of approximately. On October 21, 2018, explorer Victor Vescovo, aboard the DSV Limiting Factor, became the first person to reach the bottom of the deep. This made the Limiting Factor the deepest diving operational submersible at the time.
