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 estimated to be 36 square kilometers in size (13.9 square miles), making it the largest setting in the GTA series.

Unlike the State of Liberty or the State of Florida, much of the State of San Andreas is completely accessible to the player. The state is divided into three cities and five counties, the cities of Los Santos, San Fierro and Las Venturas, and the counties of Red County, Flint County, Whetstone, Tierra Robada and Bone County.