San Andreas is a fictional state in Grand Theft Auto: San Andreas, based on the real states of California, Nevada, Arizona and Oregon. San Andreas appears to be comprised entirely of islands as the state is surrounded by water, however, several maps throughout the state depict the northern regions (Tierra Robada and Bone County) connecting to the mainland. San Andreas is DYOM's main location.
Los Santos is the largest city in San Andreas. It is based on Los Angeles, California. It is filled with references to famous L.A. landmarks, including the Hollywood Sign, the Watts Towers, the Capitol Tower, the U.S. Bank Tower and the Santa Monica Pier among many others. It borders Red County to the north and Flint County to the west. Los Santos also includes several fictional boroughs that resemble cities in L.A. County such as Ganton (Compton), Idlewood (Inglewood) and Vinewood (Hollywood).
San Fierro is the smallest city in San Andreas, situated on a peninsula in the western portion of the state. It is a fictional city based on the real city of San Francisco, California, with the additional references of two Firth of Forth bridges in Scotland, the Forth Bridge and the Forth Road Bridge, the latter being made to also resemble the San Francisco-Oakland Bay Bridge in both design and physical location. South of San Fierro lies the massive Mount Chiliad and the little town of Angel Pine in Whetstone. North of the city, across the Gant Bridge (San Fierro's version of the Golden Gate Bridge), lies the small town of Bayside. Northeast of the city lies the county of Tierra Robada. To the east is the Panopticon, and to the southeast is Flint County.
The city bears visible scars of an earthquake, a likely reference to the Loma Prieta earthquake of 1989, 3 years before the game takes place. However, news on the radio reports on the aftermath of an earthquake early in the game, suggesting that a major earthquake had hit the state recently.
Las Venturas is a fictitious city based on Las Vegas, Nevada. It is the second largest city in San Andreas, and like its real-life counterpart, Las Venturas is located in a desert region and enjoys legalized gambling, sporting casinos such as The Camel's Toe and Caligula's Palace
The city is also notable for its freeway system. The Julius Thruway is a freeway that circles the whole city. Freeways from both Los Santos and San Fierro intersect with it. Another major road is the Harry Gold Parkway, which runs through the middle of the city and intersects twice with the Julius Thruway and then leads to Los Santos (though it is not called the Harry Gold Parkway once it leaves the city).