It occupies part of the 340 hectares of land reclaimed from Victoria Harbour in the 1990s to construct a highway and rail link to the new Hong Kong International Airport, and integrates the Kowloon station of the Hong Kong Mass Transit Railway, which serves the Tung Chung line and the Airport Express Line.

The name Union Square is not well known and is seldom used, as people tend to refer the area to its constituent parts, such as the Elements mall, the ICC, the W Hotel and the various luxurious private apartment complexes.

The master plan for Union Square, comprising the massive air rights development surrounding Kowloon Station, was laid out by TFP Farrells.

The architects envisioned a three-dimensional mixed-use urban quarter, with numerous towers sitting atop a massive podium.

The Elements Mall on the upper decks takes up 146,000 square metres (1,570,000 sq ft), with retail space occupied by luxury brands, chain stores, a cinema, a supermarket, restaurants, and an ice rink.

[1] Although Union Square was conceived as an interconnected space centred on transport infrastructure, it was criticised in a 2013 University of Hong Kong study as being cut off from its surroundings, especially for pedestrians.

Paul Zimmerman said Union Square is "an island of the rich disconnected from its surroundings", and a lesson for future urban planners.

[1] The Waterfront (Chinese: 漾日居; Cantonese Yale: Yeuhng yaht gēui) serves as the phase I of Union Square complex, and was developed by the consortium led by Wing Tai Asia, including Temasek Holdings, Singapore Land, Keppel Land, Lai Sun Development, World-wide Investment and USI Holdings.

[23] The Sorrento (Chinese: 擎天半島; Cantonese Yale: Kìhngtīn Bundóu) is a residential complex occupying the northern edge of Union Square.

[23] The Harbourside (Chinese: 君臨天下; Cantonese Yale: Gwānlàhm Tīnhah) is a 255 m (836.6 ft) tall residential skyscraper in Union Square, and serves as the phase 4 of the Kowloon station development.

The gaps between the towers help relieve the stress caused by wind since the complex has a large surface area, allowing it to act as a sail.

[23] The Arch (Chinese: 凱旋門; Cantonese Yale: Hóisyùhn mùhn) is an 81-floor 231-metre (758 feet) tall skyscraper completed in 2006 in Union Square.

[23] The Cullinan (Chinese: 天璽; Cantonese Yale: Tīnsáai), phase 6 of Union Square, is a residential complex developed by Sun Hung Kai Properties.

The International Commerce Centre (ICC), which serves as phase 7 of Union Square, is a 118-floor, 484-meter (1,588 ft) commercial skyscraper completed in 2010, owned and jointly developed by MTR Corporation and Sun Hung Kai Properties.

[29] Union Square can be accessed easily by public transportation, including MTR, Kowloon Motor Bus and the minibus services.