<P> Coordinates: 11 ° 21 ′ N 142 ° 12 ′ E ﻿ / ﻿ 11.350 ° N 142.200 ° E ﻿ / 11.350; 142.200 </P> <P> The Mariana Trench or Marianas Trench is the deepest part of the world's oceans . It is located in the western Pacific Ocean, an average of 200 kilometres (124 mi) to the east of the Mariana Islands, in the Western Pacific East of Philippines . It is a crescent - shaped scar in the Earth's crust, and measures about 2,550 km (1,580 mi) long and 69 km (43 mi) wide on average . It reaches a maximum - known depth of 10,994 metres (36,070 ft) (± 40 metres (130 ft)) at a small slot - shaped valley in its floor known as the Challenger Deep, at its southern end, although some unrepeated measurements place the deepest portion at 11,034 metres (36,201 ft). For comparison - if Mount Everest were dropped into the trench at this point, its peak would still be over 1.6 kilometres (1 mi) underwater . In 2009, Marianas Trench was established as a United States National Monument . </P> <P> At the bottom of the trench the water column above exerts a pressure of 1,086 bars (15,750 psi), more than 1,000 times the standard atmospheric pressure at sea level . At this pressure, the density of water is increased by 4.96%, so that 95 litres of water under the pressure of the Challenger Deep would contain the same mass as 100 litres at the surface . The temperature at the top is 1 to 4 ° C (34 to 39 ° F). </P>

Which part of the ocean is the deepest