Commercial Bay was the bay on the southern side of the Waitemata Harbour, formerly defining the original extent of the Auckland waterfront, Auckland, New Zealand. It was framed by two substantial headlands, Smale's Point dividing it from Freemans Bay in the west and Point Britomart dividing it from Official Bay and Mechanics Bay in the east. The Waihorotiu Stream drained the valley running down to the bay. Commercial Bay was so named because from early on it had been intended as the site for the new city's business centre, in distinction from Official Bay, where government officers were first based.
Queen Street was formed down the valley, alongside the Waihorotiu, and eventually the stream was covered over. The headlands on both sides of the bay were quarried away roughly within the 1860-1920 period, as Auckland used their stone as fill to reclaim seashore land for the growing city and built a new waterfront with various large quays. Nowadays, the former bay and its headlands are mostly covered with high-rise buildings.
Commercial Bay was where Logan Campbell erected his tent 1840 after hearing that Auckland was to become the capital of the colony. William Swainson described it thus in 1853:
Already in 1859, a new seawall had been built running from Fort Street (previously Fore Street - along the foreshore) to the newly constructed Customs Street East, and this formed the boundary for the first 9 acres (36,000 m2) of infill, straightening the previously curved coastline. By this time Smale's Point was already being quarried for fill and to allow easier passage to Freemans Bay. In the 1870s and 1880s, Point Britomart followed, to provide fill for Mechanics Bay.
By 1955, around 1.6 square kilometres (390 acres) of land had been filled in, and Commercial Bay had long since ceased to exist as a recognizable landscape feature.
Coordinates: 36°50′45″S 174°46′06″E / 36.8457°S 174.7684°E