As the longest river that is entirely confined to Belize, it drains primarily the eastern part of the Orange Walk District during its north-northeasterly course and empties into the Chetumal Bay.

[1] The New River is a habitat for numerous types of fish and birds, as well as Morelet's crocodiles.

[2][3] The New River is host to a diverse array of wildlife including freshwater fish, birds, turtles and Morelet's crocodiles.

[6] Sugarcane production along with other factors has caused large amounts of industrial and agricultural runoff to enter the New River since at least the mid 1900s.

The eutrophication caused mass die-offs in the rivers fish populations and posed a health risk for people living near the river, including in the La Inmaculada RC School where students faced health issues and had their classes suspended.