The river winds through the towns of Catigbian, Antequera, Balilihan, and Maribojoc to its mouth at Cortes.

[4] At its mouth, the river opens up to an estuary, which consists of a mixed mangrove and nipa swamp.

[5][6][7] Historically prior to road construction, the river served as a waterway for the people going to and from the interior towns.

[5][6] The Abatan River estuary is home to the following true mangrove species (with local names in parentheses):[5] Animal varieties include mudskippers, rats, fruit bats like the Large flying fox (Pteropus vampyrus), lizards like the mangrove skink (Emoia atrocostata) and water monitor (Varanus salvator), as well as ants, spiders and fiddler crabs.

[5] A new species of shipworm (Lithoredo abatanicus) was identified in the river in June 2019, locally known as Antingaw.