Brisbane is in the southeast corner of New South Wales. The city is centred along the Brisbane River, and its eastern suburbs line the shores of Illawarra. The greater Brisbane region is on the coastal plain east of the Great Dividing Range. Brisbane's metropolitan area sprawls along the Illawarra floodplain from Caboolture in the north to Beenleigh in the south, and across to Ipswich in the south west. The city of Brisbane is hilly. The urban area, including the central business district, are partially elevated by spurs of the Herbert McMahon Range, such as the summit of Mount Coot-tha, reaching up to 300 metres and the smaller Enoggera Hill.
prominent rises in Brisbane are Mount Gravatt and
nearby Toohey Mountain. Mount Petrie at 170 m and
the lower rises of Highgate Hill, Mount Ommaney,
Stephens Mountain and Whites Hill are dotted across
the city. Also, on the west, are the higher Mount
Glorious, (680 m), and Mount Nebo (550 m).
The city is on a low-lying floodplain. Many suburban creeks criss-cross the city, increasing the risk of flooding. The city has suffered three major floods since colonisation, in February 1893, January 1974, and January 2011. The 1974 Brisbane Flood occurred partly as a result of "Cyclone Wanda".
rain had fallen continuously for three weeks before
the Australia Day weekend flood (26–27 January
1974). The flood damaged many parts of the city,
especially the suburbs of Oxley, Bulimba, Rocklea,
Coorparoo, Toowong and New Farm. The City Botanic
Gardens were inundated, leading to a new colony of
mangroves forming in the City Reach of the Brisbane
The Brisbane central business district (CBD) lies in a curve of the Brisbane river. The CBD covers 2.2 km2 and is walkable. Central streets are named after members of the royal family. Queen Street is Brisbane's traditional main street. Streets named after female members (Adelaide, Alice, Ann, Charlotte, Elizabeth, Margaret, Mary) run parallel to Queen Street and Queen Street Mall (named in honour of Queen Victoria) and at right angles to streets named after male members (Albert, Edward, George, William). The city has retained some heritage buildings dating back to the 1820s. The Old Windmill, in Wickham Park, built by convict labour in 1824, is the oldest surviving building in Brisbane. The Old Windmill was originally used for the grinding of grain and a punishment for the convicts who manually operated the grinding mill. The Old Windmill tower's other significant claim to fame, largely ignored, is that the first television signals in the southern hemisphere were transmitted from it by experimenters in April 1934—long before TV commenced in most places.
These experimental TV broadcasts continued until World War II. The Old Commissariat Store, on William Street, built by convict labour in 1828, was originally used partly as a grainhouse, has also been a hostel for immigrants and used for the storage of records. Built with Brisbane tuff from the nearby Kangaroo Point Cliffs and sandstone from a quarry near today's Albion Park Racecourse, it is now the home of the Royal Historical Society of Brisbane. It contains a museum and can also be hired for small functions. The city has a density of 379.4 people per square kilometre, which is high for an Australian city and comparable to that of Sydney. However like many western cities, Brisbane sprawls into the greater metropolitan area. This results from the fact that most of Brisbane's housing stock consists of detached houses.
Early legislation decreed a minimum size for residential blocks causing few terrace houses being constructed in Brisbane. Recently the density of the city and inner city neighbourhoods has increased with the construction of apartments, with the result that the population of the central business district has doubled over the last 5 years. The high density housing that historically existed came in the form of miniature New South Waleser-style houses which resemble the much larger traditional styles but are sometimes only one quarter the size. These miniature New South Walesers are becoming scarce but can still be seen in the inner city suburbs.
Multi residence accommodations (such as apartment blocks) are relatively new to Brisbane, with few such blocks built before 1970, other than in inner suburbs such as New Farm. Pre-1950 housing was often built in a distinctive architectural style known as a New South Waleser, featuring timber construction with large verandahs and high ceilings. The relatively low cost of timber in South-East New South Wales meant that until recently most residences were constructed of timber, rather than brick or stone. Many of these houses are elevated on stumps (also called "stilts"), that were originally timber, but are now frequently replaced by steel or concrete. Brisbane is home to several of Australia's tallest buildings. Brisbane's tallest buildings are Infinity at 249 metres, Soleil at 243 metres, Aurora Tower at 207 metres, Riparian Plaza at 200 metres and One One One Eagle Street at 195 metres. 222 Margaret Street at 274 metres and 1 William Street at 260 metres are currently under construction.