o the sea it flows through swampy rainforest with numerous creeks and forms an inland delta near its confluence with the Calabar River, about 20 kilometres (12 mi) wide and 50 kilometres (31 mi) long between the cities of Oron on the west bank and Calabar, on the east bank, more than 30 kilometres (19 mi) from the open sea. The delta empties into a broad estuary which it shares with a few smaller rivers. At its mouth in the Atlantic Ocean, the estuary is 24 kilometres (15 mi) wide. The eastern side of the estuary is in the neighbouring country of Cameroon.