The peninsula began as part of the Dunedin Volcano, whose eruptions built up layers of rock between 13 and 10 million years ago. Harbour Cone, the aptly named peak visible from across the water, still shows its volcanic origins clearly. Erosion carved the valley that became Otago Harbour, leaving the peninsula as one wall of an ancient caldera. The terrain is steep and dramatic. Mount Charles rises to 408 meters, Highcliff reaches 381, and the Pacific coast drops away at Lovers' Leap in 250-meter cliffs. Two tidal inlets, Hoopers and Papanui, punctuate the outer coastline, separated by the headland of Cape Saunders. The peninsula connects to the mainland by a narrow isthmus barely 1.5 kilometers wide, a geological thread holding together two very different landscapes.

At the harbor entrance, the peninsula rises to Taiaroa Head, where northern royal albatrosses raise their chicks in full view of a public observation center. These birds, with wingspans exceeding three meters, are found breeding on inhabited mainland nowhere else on Earth. Below the headland, New Zealand fur seals haul themselves onto rocks, and yellow-eyed penguins, among the rarest penguin species in the world, shuffle up the remote beaches at dusk. The tidal inlets teem with wading birds: spoonbills stepping deliberately through the shallows, plovers skittering along mudflats, herons standing motionless in wait. Offshore, the deep submarine canyon near the peninsula creates upwellings that attract dusky dolphins, orcas, and seasonal populations of southern right whales. Marine biologists consider the waters off the peninsula one of New Zealand's most significant coastal ecosystems.

Long before European settlers built dry stone walls in the pattern of Scottish Galloway dykes, Polynesian navigators found the peninsula. Archaeological sites cluster along its shores, dating back to the earliest period of human settlement in New Zealand around 1300 AD. At Little Papanui, the lowest occupation layers may reach back to 1150 AD. Whale-ivory chevron pendants crafted by those early inhabitants are now displayed in the Otago Museum. The settlement at Harwood Township was one of the largest in the region, occupied continuously enough to be considered permanent rather than seasonal. Three pounamu adzes found nearby, described by anthropologist H.D. Skinner as the finest of their type, represent a form already archaic when they were made. Southern Maori oral tradition names five peoples who arrived in succession, the earliest now wrapped in legend but likely representing real communities whose stories compressed over centuries into myth.

European settlement began at Otakou, the old whaling station near the harbor mouth where the first organized settlers arrived aboard the John Wickliffe in 1848. The Otago gold rush of 1861 transformed the region almost overnight, and as Dunedin boomed into New Zealand's wealthiest city, the peninsula prospered alongside it. A lighthouse went up at Taiaroa Head in 1864. Prison laborers built the winding harbourside road with its distinctive seawalls of local stone. Farmers fenced 6,000 acres by the end of the 1860s, and by 1880 a third of the peninsula was in production, mostly dairy. The toll road along the harbor became popular with cyclists in the 1890s, who lobbied hard against what they considered highway robbery: five shillings for a round trip by bicycle. Their persistence paid off. The toll dropped incrementally until it was abolished entirely in 1908, a small victory for recreation over revenue.

The Pacific beaches remain the peninsula's wildest feature. Victory Beach takes its name from a 19th-century shipwreck, and its rock formations, known locally as The Pyramids, rise from the sand like displaced monuments. Allans Beach and Boulder Beach lie far enough from Dunedin that even in midsummer they are often empty of people, though not of wildlife. Along the ridgeline, Highcliff Road offers views in every direction: the city to the west, the harbor below, the Pacific stretching east toward nothing for thousands of kilometers. Larnach Castle stands on this spine, and a restored Armstrong disappearing gun at a coastal defence post speaks to a time when the harbor entrance needed guarding. The population of the peninsula remains under 10,000, with most residents clustered in small harbourside communities like Macandrew Bay, Portobello, and Otakou. The wild side, facing the ocean, belongs largely to the birds.