Christchurch (Māori: Ōtautahi) is the largest city in the South Island of New Zealand, and the country's second-largest urban area. It is one third the way down the South Island's east coast, just north of Banks Peninsula which itself, since 2006, lies within the formal limits of Christchurch.

The city was named by the Canterbury Association, which settled the surrounding province of Canterbury. The name of Christchurch was agreed on at the first meeting of the association on 27 March 1848. It was suggested by John Robert Godley, who had attended Christ Church, Oxford. Some early writers called the town Christ Church, but it was recorded as Christchurch in the minutes of the management committee of the association.

The river which flows through the centre of the city (its banks now largely forming an urban park) was named Avon at the request of the pioneering Deans brothers to commemorate the Scottish Avon, which rises in the Ayrshire hills near what was their grandfathers' farm and flows into the Clyde.

The usual Māori name for Christchurch is Ōtautahi ("the place of Tautahi"). This was originally the name of a specific site by the Avon River near present-day Kilmore Street and the Christchurch Central Fire Station. The site was a seasonal dwelling of Ngāi Tahu chief Te Potiki Tautahi, whose main home was Port Levy on Banks Peninsula. The Ōtautahi name was adopted in the 1930s. Prior to that the Ngāi Tahu generally referred to the Christchurch area as Karaitiana, a transliteration of the English name.

Christchurch lies in Canterbury, near the centre of the east coast of the South Island, east of the Canterbury Plains. It is located near the southern end of Pegasus Bay, and is bounded to the east by the Pacific Ocean coast and the estuary of the Avon and Heathcote Rivers. To the south and south-east the urban portion of the city is limited by the volcanic slopes of the Port Hills separating it from Banks Peninsula. In 2006, Banks Peninsula was incorporated into the city, in effect tripling the city's land area while adding only about 8,000 people to the city's population. To the north the city is bounded by the braided Waimakariri River.

Christchurch is one of only eight pairs of cities in the world that has a near-exact antipodal city. Half of these antipodal pairs are in New Zealand and Spain/Morocco – with A Coruña, Spain as Christchurch's antipode.

Christchurch has one of the highest-quality water supplies in the world, rated one of the purest and cleanest water in the world. The water is sourced via more than 50 pumping stations from aquifers which conduct it from the foothills of the Southern Alps and provide natural filtering.

At the centre of the city is Cathedral Square, surrounding the Anglican cathedral, Christ Church. The area around this square and within the "four avenues" of Christchurch (Bealey Avenue, Fitzgerald Avenue, Moorhouse Avenue and Deans Avenue) is considered the central business district of the city. The central city also has a number of residential areas, including Inner City East, Inner City West, Avon Loop, Moa Neighbourhood & Victoria.

Cathedral Square is a popular destination and hosts attractions such as the speakers' corner made famous by the Wizard of New Zealand, Ian Brackenbury Channell, and evangelist Ray Comfort. The central city includes the pedestrianised Cashel Street as Christchurch's urban mall. At one end of the mall stands the Bridge Of Remembrance; at the other end the old location of the amphitheatre known as the Hack Circle.

The Cultural Precinct provides a backdrop to a vibrant scene of ever-changing arts, cultural, and heritage attractions within an area of less than one square kilometre. The Arts Centre, the Canterbury Museum and the Art Gallery are located in the Cultural Precinct. The majority of the activities are free and a printable map is provided.

Christchurch has a history of involvement in Antarctic exploration – both Robert Falcon Scott and Ernest Shackleton used the port of Lyttelton as a departure point for expeditions, and there is a statue of Scott, sculpted by his widow, Kathleen Scott, in the central city.

Within the city the Canterbury Museum preserves and exhibits many historic artifacts and stories of Antarctic exploration.

Christchurch International Airport serves as the major base for the Italian and United States Antarctic programs as well as the New Zealand Antarctic programme. The International Antarctic Centre provides both base facilities and a museum and visitor centre focused upon current Antarctic activities. The United States Navy and latterly the United States Air National Guard, augmented by the New Zealand and Australian air forces, use Christchurch Airport as take-off for the main supply route to McMurdo and Scott Bases in Antarctica. The Clothing Distribution Center (CDC) in Christchurch, has more than 140,000 pieces of extreme cold weather (ECW) gear for issue to nearly 2,000 U.S. Antarctic Program (USAP) participants in the 2007-08 season.