California, or mainly Los Angeles. Rap artists often throw the WestSide sign meaning they are from Los Angeles. To be really from the WestSide, you have to be a gang-banger. Probally Black or Hispanic or Armenian. WestSide is more of a gang lifestyle.
Whiteboy: Westside blood nigga all day (screams out while wearing an LA hat)
18th Street gang member sees this: fucking lame ass whiteboy (takes out a gun and ends the wannabe motherfuckers life