The mall site is approximately rectangular, bounded by E Street / Broadway Circle (to the north), Fourth (on the east), G (south), and First (west).

The three-level central courtyard, which Jerde called an "armature" for pedestrians,[4]: 226  runs diagonally between the southwest and northeast corners.

[8] The main pedestrian entrance was near Broadway Circle next to the Macy's store, leading into the northeast end of the central courtyard / armature through a pastel colonnade.

[9] The underground Lyceum Theatre is marked by an obelisk next to the main entrance at Broadway Circle, next to a statue of mall developer Ernest W. Hahn.

Approximately halfway along the central courtyard, a triangular black-and-white striped loggia named the Palazzo Building[10] housed escalators extending the height of the mall,[11] likened to the Siena Cathedral in 1986 by The New York Times.

The building's postmodern design featured mismatched levels, long one-way ramps, sudden drop-offs, dramatic parapets, shadowy colonnades, cul-de-sacs, and brightly painted facades constructed around a central courtyard.

[13] An initial design for the Horton Plaza Redevelopment Project, featuring mainly public park space with a small retail section, was commissioned by the city of San Diego and completed in 1973 by Rockrise, Odermatt, Mountjoy and Amis.

[14]: 87  Jerde called the central courtyard an "armature", functioning as a three-storey pedestrian street with entrances aligned with the city blocks outside, featuring two shallow arcs designed to encourage meandering.

The proposal, which included office buildings and the federal courthouse complex, was adopted by the San Diego City Council in 1972.

[6] Local developer Ernest Hahn signed an exclusive negotiating contract in 1974 and purchased the land for US$1 million in 1978, conditioned on building parking garages.

[18] In August 1979, the city council approved Hahn's plans to proceed with the construction of Horton Plaza, starting with the relocation of many businesses and the demolition of several historic structures, including the Lyceum, Cabrillo, and Plaza Theatres[a] and the Horton Grand Hotel;[18] several buildings that were on the National Register of Historic Places were removed and/or relocated to make way for the planned retail center.

The Musicland Group filed for Chapter 11 bankruptcy in January 2006, and in February it announced the closing of 226 Sam Goody and 115 Suncoast Motion Picture Company stores and all Media Play locations.

On January 11, 2011, the San Diego City Council unanimously approved a plan to raze the former Robinsons-May building on the north side of the mall to make way for a 37,000 square feet (3,400 m2) urban park, effectively enlarging the adjacent, historic Horton Plaza and Broadway Fountain.

Horton Plaza Park will have a 53,000 square-foot venue, a Cabrillo Theater, an interactive pop-jet fountain, and 23-foot-tall color-changing statues.

[41] On November 22, 2016, a local woman who had previously been reported as suicidal shot herself in the middle of the crowded mall after leading police on a chase.

[42] In July 2017, a shooting occurred at the mall in which an active-duty Navy personnel was killed and his cousin wounded after getting into a confrontation with another man.

[47] The proposed redevelopment came under fire from architecture preservationists, who worked to corral votes to persuade city leaders to declare Horton Plaza a historic building.

[51] The San Diego City Council approved a land use exemption unanimously on May 20, 2019, which allowed Stockdale to proceed with its plan by reducing the required amount of retail space at the site.

When you go from a fortress-like retail center ... and you remove all of those bridges and barriers that actually separated it from the community, ... this property returns to being part of downtown.