The city of Nicolet is near its mouth on the lake Saint-Pierre which is crossed to the northwest by the St. Lawrence River.

[3] As for the section downstream from Saint-Léonard-d'Aston, it is composed of sedimentary rocks (schist, dolomite, limestone, sandstone) in horizontal strata of the St. Lawrence Lowlands.

[3] The unconsolidated deposits of the Quaternary of the St. Lawrence Lowlands are composed of clay, sand and gravel from the retreat of the Champlain Sea and peatlands.

[5] The Abenakis call it Pithiganitekw, which means 'river of the entrance', due to the fact that it flows near the outlet of lake Saint-Pierre.

[5] The toponym "rivière Nicolet" was made official on December 5, 1968 at the Commission de toponymie du Québec.