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