It is the longest river in the country and creates the border between Suriname and the East Berbice-Corentyne region of Guyana.

[3] It originates in the Acarai Mountains and flows northward via the Boven (Upper) Courantyne which is the source river for approximately 724 km (450 mi) between Guyana and Suriname, emptying into the Atlantic Ocean near Corriverton, Guyana and Nieuw Nickerie, Suriname.

Small ocean-going vessels are able to navigate the river for about 120 km (75 mi) to Apura, Suriname.

This conflict, which has been fueled since the colonial era, was solved in 2007 by a verdict by the Hague Arbitration Court, which settles the border between Guyana and Suriname on the left bank of the river, and the river water body belonging to Suriname.

The tribunal that defined the maritime boundary between Suriname and Guyana in 2007 confirmed Surinamese sovereignty over the full width of the entire Courantyne River.