It is a left tributary of the Rio Negro, which it enters just west of the city of Manaus.

The Tarumã Açu River originates with a spring in the community of Nova Canã, at kilometre 40 of the BR-174 highway.

[1] It drains the east part of the Tarumã Açu – Tarumã Mirim section of the Rio Negro Left Bank Environmental Protection Area, which is mainly covered by dense rainforest but has areas of open tropical forest and campinarana.

[2] The lower section of the river corresponds to the western boundary of the Manaus urban area.

Several of its left bank tributaries originate in the Adolfo Ducke Forest Reserve and cross the north and west zones of Manaus.