From its source, the Pozer River flows on 26.9 kilometres (16.7 mi) divided into the following segments: Its winding course extends for approximately 25 kilometres (16 mi) in a northeast direction, crosses the municipality of Saint-Benoît-Labre, the former municipality of Aubert-Gallion, flows into the Parc des Sept-Chutes, up to its confluence with the Chaudière River at Saint-Georges.

This name, still attested on a map of 1864 in the form of "Rivière Gagnon", would evoke a pioneer (or a family group) established in this zone.

The current name of the river recalls the family of John George Pfo(t)zer (the spelling became Pozer), who acquired the Aubert-Gallion seigneury in 1808.

It probably evokes more specifically Christian Henry Pozer (1835-1884), lawyer, born and died in the manor of Aubert-Gallion.

Throughout his career, he devoted himself actively to the erection of new townships, mining exploration and the construction of railways in Beauce[2] The toponym "Pozer River" was made official on December 5, 1968, at the Commission de toponymie du Québec.