Onerahi, for half a century known as Grahamtown, is a seaside suburb of Whangārei, New Zealand's northernmost city. It is the city's only seaside suburb. It is located 9 km south-east of the centre of Whangārei and is principally a peninsula in the Whangārei Harbour, which empties into the Pacific Ocean.

Whangārei is the northernmost city in New Zealand and the regional capital of Northland Region. It is part of the Whangarei District, a local body created in 1989 from the former Whangārei City, Whangārei County and Hikurangi Town councils, to administer both the city proper and its hinterland. The city population was estimated to be 56,900 in June 2023, an increase from 47,000 in 2001.