The Challenger Deep is the deepest known point in the Earth's seabed hydrosphere, with a depth of by direct measurement from submersibles, and slightly more by sonar bathymetry (see below). It is in the Pacific Ocean, at the southern end of the Mariana Trench near the Mariana Islands group. The Challenger Deep is a relatively small slot-shaped depression in the bottom of a considerably larger crescent-shaped oceanic trench, which itself is an unusually deep feature in the ocean floor. Its bottom is about long and wide, with gently sloping sides. The closest land to the Challenger Deep is Fais Island (one of the outer islands of Yap), southwest, and Guam, to the northeast. It is located in the ocean territory of the Federated States of Micronesia, from its border with ocean territory associated with Guam.