How far does the underwater Congo Canyon extend beyond the river mouth?

The Congo Canyon is a large submarine canyon that acts as a conduit for sediments from the Congo River to the deep-sea floor.

Beyond the mouth of the river, the canyon extends offshore for approximately 125 miles (200 km). The total length of the canyon, measured from its head 17 miles (28 km) inland up the Congo Estuary to its end at the base of the continental slope, is about 175 miles (280 km).12