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Mega City is an enormous virtual megacity in which the inhabitants of the Matrix live their lives in the Matrix series. The City is a conglomeration of many cities, fused into one large city with a gigantic downtown and an impressive skyline.

The city was designed to represent an amalgam of any number of major cities in the United States during the 1990s; i.e., gray and utilitarian with small pockets of color and entertainment.

According to the films' graphic designer Suzanne Buljan, companies and utilities in the city were uniformly given generic "City" names which are seen on signage and vehicles throughout the films, such as City Metro, City Waste, City Rail, City Post and City Power:

"Everything is City-something; all the facilities are City related."

The concept of the City in The Matrix and its sequels is an archetype of the hyperreality theory proposed by Jean Baudrillard and developed by Umberto Eco; that is that the virtual "city" constructed by the machines controlling the society is more convincing and realistic to its inhabitants than the "real world" – a dystopian futur noir portrayed in stark contrast to the virtual one.

The harsh, gray, uninteresting landscape was implemented to make sure the unknowing inhabitants of the Matrix did not question their living space, lacking an alternative. It is possible that the City is an inhabitant-unique environment, in which no one sees things the same way. The visualization of the City as gray and unnatural in The Matrix could possibly be a result of the redpills' experience outside of the Matrix. Further, Agent Smith describes to a captured Morpheus that earlier instances of the Matrix which were cheerier did not meet the (subconscious) expectations of the humans hosted within; the Architect later expands on that explanation, telling Neo that the first versions failed because they were designed around two extremes (perfect paradise and absolute hell) that the human mind was unable to accept.

Mega City as it appears in the Matrix films is an amalgam of various cities of the late 20th century, in particular:

Excluding the car chase sequence in The Matrix Reloaded, the Matrix films were entirely filmed in the Australian city of Sydney.

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