Grand Theft Auto III takes place in Liberty City (based upon New York City), a city on America’s East Coast. The overall size of GTA III’s world is around three square miles. This version used in Grand Theft Auto III was also used later on in GTA: Liberty City Stories, a sequel to the story showing the events leading up to the story in GTA III. It was also used for GTA Advance and a mission called “Saint Mark’s Bistro” in GTA: San Andreas, and is one of the three renditions of Liberty City featured throughout the series.
A previous version of the city was also featured in the original Grand Theft Auto game, and a newer version was later used for Grand Theft Auto IV (2008), Episodes from Liberty City (2009) and a top-down version in GTA: Chinatown Wars (2009). Grand Theft Auto III is set around Autumn in 2001. When the game was first released, this was indicated by the Liberty Tree website, which included plot points that connect events from the beginning of the game in its last existing monthly entry, dated October 18th, 2001.
Throughout the story of GTA III, players progress through 3 islands. The player starts in Portland Island, and after completing the required amount of missions to progress, can later go over the the second island, Staunton Island. Here, the player is required to complete more missions before progressing again to the third island, Shoreside Vale, where the story concludes.