The Early Days: The islands of the Hauraki Gulf and the Coromandel Peninsula were likely places of first landfall for Polynesian migrants around 1250–1300. Archaeological investigation of middens (ancient refuse heaps) on east coast beaches of the peninsula in the 1960s, revealed evidence of moa hunting and raids on seal rookeries.
Both Te Arawa and Tainui canoes arrived in Hauraki from East Polynesia, having first made landfall at Whangaparaoa at the far eastern end of Te Moana-nui-a-Toi (the Bay of Plenty). Tainui continued to Kāwhia on the west coast, whilst Te Arawa made a final landfall at Maketū in the Bay of Plenty, but some crew members remained in Hauraki. Ngāti Hei, the descendants of Hei, the brother of Te Arawa chief Tamatekapua, and Ngāti Huarere, the descendants of his grandson Huarere, dominated Hauraki for 300 years. In the 2000s Ngāti Hei retain their Te Arawa identity and affiliation.
It is known that the Arawa canoe, which landed in the Northern Coromandel Peninsula during the Great Migration, was captained by Tamatekaupua. He is buried on Morehau Mountain. There is nothing specifically recorded about the Maori settlement in Onemana itself.
Onemana and Opoutere are adjacent areas of land near the base of the Coromandel Peninsula. It is likely that in the days of pre European settlement in the area there would be traffic between such near neighbours. By the 16 th century the Ngati Hei, Ngati Huarere and Ngati Hako were living in the Coromandel Peninsula. The first known settlers of the Opoutere and Onemana area were the Ngāti Hei.
Frequent attacks were made on the peninsula by Tainui from the west, over the Hauraki Plains, led by Marutuahu from Kawhia. The claim was that the Tainui canoe had visited the region around the same time as the Arawa canoe made land fall, hence they had a claim to the area.
Only Ngatei Hei and Ngatei Hako survived these attacks with their own mana and identity intact. The Tainui victors absorbed the survivors of the other tribes.
In the Opoutere and Onemana area the Ngatei Hei were supplanted by the Ngati Hako in the mid 17th century. Then during the Nga Puhi raids of the Musket Wars, in the early 19th century, the area was left without a permanent population.
The few survivors fled in land from vulnerable pa sites – eventually inter marrying with the Bay of Plenty and Tainui. This may have been the historical fate of the Pa site on the southern bluff of the Onemana Beach. Given the Pre European history of the area the word Onemana may mean spiritual and prestigious.
European Settlers Arrive: In the 1870s and 1880s gold prospectors staked claims on quartz outcrops around the Wharekewa Harbour, resulting in half a dozen major gold strikes, and several mines being established in the 1890s. Kauri logging was also underway in the 1890s and as it petered out, gum diggers moved in. At the start of the 20th century, there was a settlement of
about 50 people near the mouth of the Wharekawa Harbour, with a store, a bakery and a post office. An Anglican church was built but was taken over by Ringatu worshippers. As the forest disappeared and the gum industry declined in the 1920s, the village also declined. By the late 1930s, the shops had closed, and the church had been abandoned. Farming and the planting of pines for the Tairua State Forest gradually healed the land.
After World War II a few families from Auckland and Hamilton built baches beside the Wharekawa Harbour, and in the 1950s a holiday store and a camping ground opened. Three small subdivisions were established in the late 1960s and 1970s, but the local community resisted further development during the 1980s.
Further south in the area of Onemana, rural and forestry areas were also established, but the village of Onemana itself was only developed in the 1970s within the boundaries of a farm named Shang-ri-la. The Bambury family developed the village and the original development was subject of several restrictions, particularly the limit on the area of development.
The village of Onemana consists of 364 sections while Crown land covers most the northern and western areas of the hills of the Onemana peninsula. This is currently under forestry lease and provides a backdrop to the village. The rural area to the south of the Onemana village is currently in private ownership and land use varies from olives and orchards to grazing. Access to these properties is by an unsealed road that also serves as a forestry road. The rural area to the west of State Highway 25 is also part of Onemana, being a mix of grazing and lifestyle properties.