It was named by the Street Naming Committee on 23 May 1837 after King William IV, the then reigning monarch, who died within a month. It is historically considered one of Adelaide's high streets, for its focal point of businesses, shops and other prominent establishments. In August 1977, the first bus lane in Adelaide opened along King William Street from Victoria Square to North Terrace.
Description
The name King William is applied several times to the continuous stretch of road that begins in the inner southern suburbs and terminates in North Adelaide. Where it runs through the Adelaide city centre from South Terrace to North Terrace, it is named "King William Street"; elsewhere it is named "King William Road". It starts in the south as King William Road, at the north edge of Heywood Park in Unley Park, and runs through Hyde Park and Unley to Greenhill Road. The road through the south parklands is named Peacock Road after Caleb Peacock who was Mayor of Adelaide from 1875 to 1877. Through the Adelaide city centre it is King William Street and continues north from North Terrace as King William Road to Brougham Place, North Adelaide. At approximately wide, King William Street is the widest main street of all the Australian State capital cities. The road continues north to National Highway 1 as O'Connell Street, but the name King William is not again used. The northern section called King William Road passes several of Adelaide's landmarks, including Government House, Elder Park, the Adelaide Festival Centre, Adelaide Oval and St Peter's Cathedral. The section from North Terrace over the Adelaide Bridge to Pennington Terrace was named King William Road at the opening of the bridge in 1877. building on the right has since been demolished, as have the two buildings next to it. Until the 1960s, trams used King William Street as a major backbone of the network, with a grand union junction at North Terrace and only one pair of tracks missing between Grenfell and Currie Streets. When most of the tram lines were dismantled in the 1950s, only the Glenelg tram line remained, and it used King William Street between South Terrace and its terminus at Victoria Square. In 2007, the tram line was extended to run the full length of King William Street again, turning left onto North Terrace and terminating at Adelaide railway station, later extended westwards via Port Road to the Adelaide Entertainment Centre. In 2018, another expansion of the tram routes replaced the turn at the intersection of North Terrace and King William Street with a junction, and a short spur to a stop outside the Adelaide Festival Centre as well as an eastward extension along North Terrace to the Adelaide Botanic Garden. Tracks go in all four directions, but not all turning movements are supported.
Between North Terrace and South Terrace, all east-west roads change their names as they cross King William Street. It is said this is because no one was allowed to "cross the path of a monarch". Travelling south from North Terrace, the street pairs are:
