The PS2 USA BIOS is the official system file needed to run North American PlayStation 2 games on the PCSX2 emulator. It provides the core functions of the original console, such as starting games, managing memory cards, and ensuring region compatibility. To use it, the BIOS must be placed in the **“bios” folder** inside the PCSX2 directory and then selected through the emulator’s settings. Since it is copyrighted software, the only legal way to obtain the PS2 USA BIOS is by dumping it directly from your own PlayStation 2 console, rather than downloading it from unofficial sources.