Ankobra, river in southern Ghana, western Africa. Rising northeast of Wiawso, it flows about 120 miles (190 km) south to the Gulf of Guinea (Atlantic) just west of Axim, commercial centre of the river basin. Its chief tributaries are the Mansi and the Bonsa rivers, and much of its basin is shared with the Tano River to the west. There are rapids in the upper reaches, but the Ankobra is navigable for 50 miles (80 km) upstream from its mouth and is tidal as far as Tomento, with a 2-foot (0.6-metre) low- to high-tide difference.