The peninsula is steep and hilly, and is largely covered in temperate rainforest. The Coromandel Range forms a spine for the peninsula, rising to nearly 900 meters, and the large island of Great Barrier, which lies beyond the northern tip, can be thought of as an extension of the range. Great Barrier is separated from Cape Colville on the peninsula’s northern coast by the Colville Channel.
Although the peninsula is close to large centers of population such as Auckland to the west and Tauranga to the southeast, its rugged nature means that much of it is relatively isolated, and the interior and northern tip are both largely undeveloped and sparsely inhabited. A forest park covers much of the peninsula’s interior.
Numerous small islands and island groups lie offshore, such as the Motukawao Islands to the northwest, the Alderman Islands and Slipper Island to the southeast, and the Mercury Islands to the northeast.
The peninsula shows considerable signs of past volcanism. It comprises the eroded remnants of the Coromandel Volcanic Zone, which was highly active during the Miocene and Pliocene periods. Volcanic activity has since primarily shifted southeast to the Taupo Volcanic Zone, although Mayor Island was recently active some 25 km to the east. Geothermal activity is still present on the Peninsula, with hot springs in several places, notably at Hot Water Beach, in the central east coast between Whitianga and Tairua.
