General Post Office, Adelaide

General Post Office, a colonial-era building situated on 141 King William Street on the north-west corner of King William Street and Victoria Square, is the former General Post Office for South Australia.

Postal services operated from the building between 6 May 1872 and 11 October 2019. Construction began on the site to build a multi-level building above the GPO in 2021, with the new Adelaide Marriott Hotel slated to open in July 2024.

History
The original building was constructed in the period 1867–1872, and was the most expensive building constructed to that time by the colonial government in South Australia. It was constructed from Glen Osmond and Glen Ewin stone, and ornamented with Bath limestone.

A competition was held in March 1866 for the design of the building, with the winning design submitted by Edmund Wright in collaboration with Edward Hamilton. They were at the time in practice with Edward John Woods, and Robert G. Thomas may have had a hand in the design.

Prince Alfred, The Duke of Edinburgh, was involved in laying the foundation stone, who also officially named the clock tower Victoria Tower on 1 November 1867. The capstone was put in place at a ceremony on 25 May 1870. The height of the tower was put at 154 ft, a little taller than the Albert Tower of the Town Hall on the other side of King William Street. The original plans had the tower somewhat taller, but R. G. Thomas was obliged to redesign it, as a cost-saving measure.

The building was extended in 1891-92.

There was also an office tower addition to the original post office in the 1920s.

Conversion
On 14 October 2019, Adelaide's GPO was relocated to the adjacent GPO Exchange tower at 10 Franklin Street. The original building was planned to be turned into a retail and dining hub, with a 15-storey, 285-room Westin hotel to be built above it.

In April 2021 a sod-turning ceremony to mark the beginning of construction of the first Marriott International hotel on the site was attended by South Australian premier Steven Marshall. The 16-storey luxury hotel was estimated to cost A$200, with property developer Greaton handling the construction. Designed by local architects Baukultur, the new build, which is on the site of the 1920s office building addition, will retain the entire original GPO building, with some sections incorporated into the new hotel. Upgrades to the structure as well as additional seismic retrofit have been added, to ensure the structural integrity of both the old and new buildings. The topping out ceremony took place in October 2023, and included an Aboriginal smoking ceremony by traditional owner representatives Kuma Kaaru.

The hotel, which comprises 285 luxury rooms, is slated to open as the Adelaide Marriott Hotel in July 2024.