What is the name of the fictional city representing New York in GTA IV?

The fictional city representing New York in Grand Theft Auto IV is Liberty City.

GTA IV's Liberty City is a satirical, redesigned version of New York City, created for the game's more realistic and socially focused setting. The city is divided into borough-like areas: Broker resembles Brooklyn, Dukes resembles Queens, Bohan resembles the Bronx, and Algonquin resembles Manhattan. The neighbouring state of Alderney is modeled after New Jersey.

Rockstar conducted extensive field research in New York while designing the setting. The developers photographed neighborhoods, studied architecture and infrastructure, and used the city's cultural contrasts to shape the game's world. Liberty City is not an exact replica; it rearranges geography and exaggerates recognizable features for gameplay and satire.

A common mix-up is confusing GTA IV's Liberty City with the versions in earlier games. Liberty City appears throughout the series, but each era depicts a different continuity and design. GTA IV's version belongs to the later “HD Universe” and is specifically based on New York City.