The basin floor measures about 220 km2 (85 sq mi) and is the deepest point in the Arctic Ocean.

The Molloy Deep is a roughly rectangular, seismically active,[11] extensional,[12] sea-floor basin that lies between the northwestern tip of the Molloy Fracture Zone[13] (a right-lateral, strike-slip fault[14]) and the Spitsbergen Fracture Zone (also a right-lateral, strike-slip fault).

The Lena Trough joins the southwestern end of the Arctic Ocean's Gakkel Ridge,[15] which is the slowest-spreading mid-ocean ridge on Earth and which stretches across the entire Arctic Oceans’ Eurasian Basin.

[16][17][18] The Molloy Deep was discovered in September 1972 by the USNS Hayes (T-AGOR-16), the first of a new class of catamaran-hulled oceanographic research vessels.

[22] This is shallower than previous estimations using earlier technology with less precise bathymetric methods.