Its source is located in the province of Newfoundland and Labrador and it empties into the Gulf of Saint Lawrence in the Côte-Nord region of Quebec.

[1] It flows in a southerly direction, and empties into Esquimaux Bay in the Vieux Fort archipelago, about 35 kilometres (22 mi) west of the municipality of Blanc-Sablon.

[6] The river basin include part of the proposed Basses Collines du Lac Guernesé Biodiversity Reserve.

[8] Between July and August 2019 a team of underwater archaeologists discovered and examined four fishing sites on the Saint-Paul River that dated to the 16th century.

The camps were full of objects such as cauldrons, ceramics, roofing tiles and ships nails that the Inuit probably bought from Basques.

[13] The bed of the river is composed of medium-size rocks, and the water is cold and clear, making ideal habitat for Atlantic salmon.

Other species found at the river mouth include American eel (Anguilla rostrata), anadromous brook trout (Salvelinus fontinalis) and rainbow smelt (Osmerus mordax).