Modern sonar surveys place the deepest surveyed part of Challenger Deep at roughly 10.9 kilometers—about 36,000 feet—below sea level. It is the deepest known point in the ocean, within measurement uncertainty.
Three things to know
- Approx. depth
- 10.9 km
- Survey estimates vary by tens of meters and by the exact depression measured.
- Setting
- Subduction zone
- The Pacific Plate bends beneath the Philippine Sea Plate region.
- Pressure
- ~1,100 atm
- Approximately 16,000 psi at the deepest floor.
A trench, not a simple crack
The Mariana Trench is a long, curved subduction feature in the western Pacific. Challenger Deep is a cluster of exceptionally deep depressions near its southern end, not the full trench. Sonar maps reveal ridges and basins rather than one perfectly shaped pit.
Why the number changes
Depth measurement combines acoustic travel time, sound-speed profiles, vehicle navigation, tides and the reference sea surface. Better instruments and corrections refine the result. Different expeditions can therefore publish defensible values that are close but not identical.
Life at the bottom
Hadal amphipods, microbes and other organisms survive without sunlight under extreme pressure. Food arrives from above or is transported along slopes. The environment is isolated but not untouched: researchers have detected human-made contaminants and debris even at trench depths.
What people usually ask
Could Mount Everest fit in the trench?
Placed with its base at the deepest point, Everest’s summit would still be roughly two kilometers below sea level.
Has a person reached Challenger Deep?
Yes. Crewed descents began with Trieste in 1960, followed by later expeditions in specialized submersibles.
Here’s where the answer came from
Open the original government science or research-institution source behind this page.