Cascadia Channel is the most extensive deep-sea channel currently known (as of 1969) of the Pacific Ocean. It extends across Cascadia Abyssal Plain, through the Blanco Fracture Zone, and into . Notably, Cascadia Channel has tributaries, akin to river tributaries. Cascadia Channel has two contributing tributaries—Juan de Fuca Channel from the north, and the outflow of Quinault and in the south. The channel is believed to be over 2,200 kilometres (1,400 mi) long.