The Mariana Trench or Marianas Trench is located in the western Pacific Ocean about east of the Mariana Islands; it is the deepest oceanic trench on Earth. It is crescent-shaped and measures about in length and in width. The maximum known depth is (± ) (6.825 miles) at the southern end of a small slot-shaped valley in its floor known as the Challenger Deep. However, some unrepeated measurements place the deepest portion at . If Mount Everest were placed into the trench at this point, its peak would still be under water by more than .