The river's drainage basin covers 14,762 square kilometres (5,700 sq mi) over both Liberia and Guinea.[4] At 175 miles (282 km) in length, it is one of the six main or major rivers of Liberia.[2][4] There are only 16 rivers in the country total.[5] The average annual discharge of the St. John is 136.06 m3/s (4,805 cu ft/s) as measured at the inland station of Baila.[6] During the wet season in October, flows average 233.49 m3/s (8,246 cu ft/s), while in February during the dry season the flows average 18.95 m3/s (669 cu ft/s) at the same location.[6]
The mouth of the river is approximately 60 miles (97 km) south and east of the Saint Paul River’s mouth near Monrovia.[7] Flowing generally southwest from its source to the ocean it contains occasional rapids and a waterfall.[2] Near the ocean the river reaches its widest point of about 1 mile (1.6 km) across and is the location of Factory Island, the largest of the many islands in the river.[7] The river received its name from Portuguese explorers in the 15th Century who spotted the mouth on St. John's feast day.[2]
The Saint John River has a variety of aquatic life in and along the shores over the length to the river. Species include the Slender-snouted Crocodile on inland portions of the waterway.[8] There are at least 65 species of fish in the river, including species of Mastacembelidae, Barbus eburneensis, Chrysichthys johnelsi, Killifish, Electric catfish, Nile perch, and Tilapia among others.[9] Birds also use the riverbanks and islands as nesting grounds, including the Three-cusped Pangolin, Palaearctic, Sandpipers, Greenshanks, Little Ringed Plover, and Water Chevrotain in the Kpatawee Wetlands area in Bong County.[10]
