San Fierro, San Andreas is the second fictional city encountered in Grand Theft Auto: San Andreas, and is based on real-life San Francisco, California.

San Fierro is the second largest city in population and smallest in area in San Andreas, but the most urbanized, and is situated on a peninsula on the western part of the state. South of the city lies the massive Mount Chiliad and the small town of Angel Pine in Whetstone. To the north of the city, across a re-creation of the famous Golden Gate Bridge (Gant Bridge), lies the town of Bayside, and northeast of the city lies the county of Tierra Robada. San Fierro is a moderately sized city with the beautiful San Fierro Bay to the north and The Panopticon to the east. San Fierro is connected to Los Santos and Las Venturas by road, rail and air.

Supposedly of Spanish foundation like San Francisco, Fierro is old Spanish for Hierro (Iron), not a likely name for a saint. The name derives from the motto for the city of San Francisco, "Oro en Paz, Fierro en guerra", Spanish for "Gold in Peace, Iron in War".

There is a sizeable country club complete with a golf course within San Fierro. In addition to this, San Fierro has a district marked by rainbow signs that is meant to emulate San Francisco's famous Castro District, home to a sizeable homosexual population. San Fierro is also home to the football team, the San Fierro 69ers, a double entendre referring to both the San Francisco 49ers and the "69" sexual position. Furthermore, in a crude reference to anal sex, the city's baseball team, the San Fierro Packers, is sponsored by none other than Fierro Fudge.

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, though dialogue suggests that an earthquake has occurred just recently. The most obvious sign of the intense damage is the crumbled section of freeway lying to the immediate west of Garver Bridge's San Fierro approach, which is an apparent emulation of the damage done to San Francisco's Embarcadero Freeway or even the Cypress Street Viaduct in Oakland California, whose remnants could be seen for years after the earthquake. The freeway section does not seem to have any visible connection to the existing freeway, however. The city's infrastructure and buildings are not visibly damaged from the earthquake, the only such damage being in the Doherty area.