The à Âruawharo River is a river on the North Auckland Peninsula of New Zealand. It flows westward into the Kaipara Harbour west of Wellsford. It forms part of the boundary between the Northland region and the Auckland Region.
The New Zealand Ministry for Culture and Heritage gives translations of "place of [a] stretched-out pit" or "place of Ruawharo [a personal name]" for à Âruawharo.
In pre-European times, the à Âruawharo River was important to the TÃÂmaki MÃÂori people of the Kaipara Harbour. The Opou portage allowed waka to be transported across the Okahukura Peninsula between the à Âruawharo and Tauhoa rivers.