[1] It is in the James Bay drainage basin, and is a left tributary of the Ivanhoe River.

The river begins at a small, unnamed lake in geographic Gamey Township,[2] and flows north to Yohannson Lake, where it enters geographic Crockett Township.

[3] It flows briefly through the northwest corner of the township and enters geographic Sandy Township,[4] continuing its northeast course under Ontario Highway 101.

The river heads north out the lake on the Paul Township side, takes in the left tributary Little Shawmere River, then turns northeast back into Warren Township and continues northeast into geographic Lemoine Township.

[9] It passes under the Canadian National Railway transcontinental railway main line, at that point passed but not served by Via Rail transcontinental Canadian trains, at the railway point of Shawmere, and reaches its mouth at the Ivanhoe River.