Wollongong is a seaside city located in the Illawarra region of New South Wales, Australia. It lies on the narrow coastal strip between the Illawarra Escarpment and the Pacific Ocean, 82 kilometres (51 mi) south of Sydney.

With a population of 284,169 Wollongong is the 3rd largest city in New South Wales after Sydney and Newcastle, and the 9th largest city in Australia. The metropolitan area extends from Helensburgh in the north to Gerroa in the south, and is administered by the Wollongong, Shellharbour and Kiama councils.

Known affectionately as the Gong, Wollongong is a city with a long history of mining and industry, with coal mines, a steelworks and an industrial port. The city also attracts numerous tourists each year, and is a regional centre for the South Coast fishing industry. The local University of Wollongong has around 22,000 students and is internationally recognised.

Wollongong is noted for its numerous surfing beaches, scenic lookouts and botanic gardens. It has two regional cathedrals, churches of many denominations and the Nan Tien Temple, one of the largest Buddhist temples in the southern hemisphere.

The name Wollongong is believed to mean "sound of the sea" in the local Aboriginal language, although other explanations have been offered, such as "great feast of fish", "hard ground near water", "song of the sea", "sound of the waves", "many snakes" and "five islands".

The city of Wollongong has a distinct geography. It lies on a narrow coastal plain flanked by the Pacific Ocean (or Tasman Sea) to the east and a steep sandstone precipice known as the Illawarra Escarpment to the west. The coastal plain is widest in the south and narrowest in the north, with the city centre located about midway.

The escarpment ranges between 150 and 750 metres (490 - 2,460 ft) above sea level, with locally famous mountains such as Mount Keira (464m), Mount Kembla (534m), Broker's Nose (440m) and Mount Murray (768m) to the south. It contains strata of coal measures, and the adit entrances to many coal mines have been established along the slopes of the escarpment throughout Wollongong. Suburbia encroaches on the escarpment’s lower slopes in some areas, but the majority remains in a relatively natural state forested with dry sclerophyll and pockets of temperate rainforest. The escarpment is largely protected by a State Conservation Area and local council zoning, and provides a scenic backdrop to the city.

In the north the coastal plain becomes so narrow that the coastal road Lawrence Hargrave Drive once precariously hugged the cliffline until rock falls forced its closure. It was replaced in 2005 by the Sea Cliff Bridge. The bridge carries both vehicular and pedestrian traffic just off the coast, crossing the submerged rock shelf. The South Coast railway line must go through several tunnels to reach the Sydney metropolitan area. The Southern Freeway and Old Princes Highway provide alternative inland routes, descending the escarpment further south at Bulli Pass or at Mount Ousley, entering just north of Wollongong's city centre.

To the south the plain reaches its maximum extent around Albion Park where it incorporates a large coastal saltwater lagoon called Lake Illawarra, separated from the Pacific Ocean by a long sandy spit.

The coastal strip consists of highly fertile alluvium, which made Wollongong so attractive to agriculturists in the nineteenth century. It contains many hills including the foothills of the escarpment’s lower slopes, and while these generally do not exceed one hundred metres in height they give much of the city an undulating character. The coastal strip is traversed by several short but flood-prone and fast-flowing streams and creeks such as Para Creek, Allans Creek, Mullet Creek and Macquarie Rivulet.

The coastline consists of many beaches characterised by fine pale gold-coloured sands; however, these beaches are sometimes interrupted by prominent and rocky headlands jutting into the sea. In places these headlands have been excavated or extended to create artificial harbours at Wollongong, Port Kembla, Shellharbour and Kiama. Just off the coast south of Wollongong centre, near Port Kembla, lies a group of five islands known collectively as The Five Islands. The islands are a wildlife refuge.

The inner city area includes the suburbs of Wollongong and North Wollongong, extending from Para Creek in the north, west to include the Wollongong Hospital, and south to the Greenhouse Park.

The CBD is a major commercial hub containing many department stores and specialty shops, offices and entertainment venues. It is centred around the Crown Street Mall, and approximates the area bounded by Market Street, Corrimal Street, Burelli Street and the railway line. Surrounding the CBD lies a mixture of parks, reserves, light commercial property, houses and multi-story residential units. Multi-story housing is evident particularly on Smith’s Hill north-east of the CBD, reflecting the popularity of combining inner-city living, coastal views and a beachside lifestyle.

To the east of the city lies Flagstaff Point, a rocky headland with eroded low cliffs topped by a grassy hill. The northern side of the point was excavated by convict labour to form Belmore Basin, and later extended with the northern breakwater to create Wollongong Harbour. The area is the site of a historic fort, several restored canons and two lighthouses, a feature peculiar to the east coast of Australia. The older Wollongong Breakwater Lighthouse located at the harbour entrance was made of wrought iron plates in 1871 and has become an icon of the city. The newer Wollongong Head Lighthouse was constructed in 1936 atop the Flagstaff Hill and is still in use today. Belmore Basin houses the commercial fishing fleet and Fisherman’s Co-op, while the main harbour shelters private vessels.

The main beaches of central Wollongong are North Wollongong (or simply North) Beach extending from the harbour up to the Para Creek lagoon and Puckeys Estate Reserve, and Wollongong City Beach extending south from Flagstaff Point and into Coniston Beach.

The main road connecting Wollongong is the Waterfall-Yallah Southern Freeway (formerly the F6). The freeway, part of National Route 1, descends the escarpment via Mount Ousley Road to enter the city near the University of Wollongong and exits at its southern fringe. A second freeway, the Northern Distributor, continues northward from the university to connect Wollongong's northern suburbs, Bulli Pass and the scenic Lawrence Hargrave Drive. The Illawarra Highway connects Wollongong's southern suburbs to the Southern Highlands via Macquarie Pass.

Wollongong is served by the South Coast railway line. Passenger rail services on this line connect the centres of Nowra and Kiama to the south and Sydney to the north. A branch line connects suburbs between the CBD and Port Kembla. A passenger rail service connecting Wollongong to the Southern Highlands has since been replaced with a coach service. Freight services connect Sydney markets with Port Kembla and the Manildra factory at Bomaderry. The Southern Highlands line is used primarily for freight, providing an important bypass for Sydney's congested rail network.

Bus services in Wollongong are provided by Premier Illawarra, Dions Bus Service, Greens Northern Coaches and other bus companies. Wollongong railway station serves as the network's hub. Services connect Wollongong suburbs to Shellharbour, Lake Illawarra and the Royal National Park.

Wollongong is serviced by Illawarra Regional Airport, also known as the Wollongong Airport and the base for the Historical Aircraft Restoration Society (HARS). The Airport is located at Albion Park Rail, in the Shellharbour City LGA.

Wollongong maintains an active arts scene. In the area of music the city is home to the Wollongong Symphony Orchestra, BlueScope Steel Youth Orchestra, a jazz club and various groups and ensembles. The Wollongong Conservatorium of Music provides musical tuition for instruments and voice in classical, jazz and contemporary styles. It is one of the largest regional conservatorium in Australia and located in the historic Gleniffer Brae Manor House, part of the Wollongong Botanic Gardens.

Local theatre groups include the Arcadians, Roo Theatre, Merrigong and Wollongong Workshop Theatre.

The annual Wollongong Eisteddfod showcases local talent in music, theatre and dance.

The Wollongong City Gallery houses a significant collection of the art of the Illawarra, contemporary Australian, Aboriginal and Asian art. In addition there are a number of private galleries, particularly in Wollongong's northern seaside suburbs.

The popular 1990s stoner rock band Tumbleweed were formed and based in Wollongong.

Entertainment venues include the Crown Street Mall, many restaurants and cafes, the town cinemas and the Illawarra Performing Arts Centre. Adjacent to WIN Stadium, the home ground of the NRL team St. George Illawarra Dragons, is the WIN Entertainment Centre: a multipurpose venue which hosts concerts and sporting events (including Southern Stars, basketball and motocross stunt shows). There are numerous city nightclubs, pubs & Registered Clubs, including The Illawarra Master Builders Club, The Grand Hotel (back to its original name, after being called Cooney's for a few years), The Glasshouse Tavern, One Five One (Formerly Bourbon St and originally Cousins), Castros (Formerly Rusty's), The Illawarra Hotel, The Harp Hotel, and The North Wollongong Hotel. The iconic Oxford Hotel closed in 2010, which meant the demise of a well-known live music venue, home in years past to acts such as Tumbleweed in their formative days. Most suburbs also have their own hotels, each with individual character. The Headlands Hotel at Austinmer is heritage-listed.