Where is the fuel cut off switch for 2001 buick regal?

There isn't a readily accessible, easily-located fuel cut-off switch on a 2001 Buick Regal like you might find on some vehicles for emergency purposes. Modern cars generally don't include such a switch for safety and security reasons. The fuel system is controlled electronically and shuts down automatically in various crash scenarios.

To stop the fuel supply in an emergency situation, you would need to disconnect the fuel pump's electrical connection (which requires some mechanical knowledge and is not a simple or quick process). This is not recommended unless you are trained in vehicle mechanics. Disconnecting the battery's negative terminal is a safer way to shut down the vehicle's electrical system, including the fuel pump.