The Waipaoa River flows for approximately 80 kilometers from the eastern slopes of the Raukūmara Range to its mouth at Poverty Bay, just south of Gisborne. Its basin is large, covering 2,165 square kilometers, and it has formed the fertile Poverty Bay flats. The river's character is heavily influenced by extensive flood control infrastructure, including stopbanks that are part of a major scheme designed to protect agricultural land and settlements. An 8-kilometer-long cycle trail follows the top of the stopbank along the river's eastern side between the river mouth and the Matawhero State Highway 2 bridge, indicating a managed, engineered environment in its lower reaches. Major settlements along its course include Te Karaka, Ormond, and Pātūtahi.

The river holds significant cultural importance, with its Māori name, Waipaoa, meaning "Pāoa's river," referencing the captain of the Horouta canoe. The river's aesthetic includes expansive views of the river mouth and surrounding hills, farms, and agricultural areas from the stopbank trail. The area is exposed to winds from the northwest or south, which is a key consideration for any paddling or cycling activity. Paddlers should be aware of ongoing flood control work, such as stopbank upgrades along tributaries like the Whakaahu Stream near Patutahi. The river receives numerous tributaries, including the Wharekōpae, Waikohu, Mangatū, Te Ārai, Waingaromia, and Waihora rivers.