Kanmuri (冠山, Kanmuri-yama) (1,339m) and empties, through a flood-control channel, into the Seto Inland Sea.

The Ōta has numerous tributaries and branches into the delta area of Hiroshima which comprises the Tenma, Kyūōta/Honkawa, Motoyasu, Kyōbashi, and Enkō rivers.

Originally, the Ōta River passes through the western side of Aioi Bridge which was the aiming point for the atomic bombing of Hiroshima.

The original passageway of the Ōta is now known as the Kyūōta River (旧太田川, Kyūōta-gawa, lit.

Ōta River runs through the municipalities of Hatsukaichi, Akiota, Kitahiroshima, Akitakata, Higashihiroshima and Hiroshima.