The Omanaia River is a river of the Northland Region of New Zealand's North Island. It flows northwest from the Waima Forest, first as a stream and then as a silty arm of the Hokianga Harbour. The toiwnship of Rawene stands at the point where the river meets the main waters of the harbour.
"Place Name Detail: Omanaia River". New Zealand Geographic Placenames Database. Land Information New Zealand. Retrieved 12 July 2009.
Coordinates: 35°25′S 173°30′E / 35.417°S 173.500°E