An interior rearview mirror system for a vehicle includes an interior rearview mirror assembly having a reflective element. An information display is at the interior rearview mirror assembly and displays information for viewing by a driver of the vehicle. The information display may be located behind the reflective element and viewable through the reflective element by the driver of the vehicle. The mirror system includes a handheld device having a position locator and being capable of establishing a geographical position of the handheld device. The information displayed by the information display is derived at least in part via a wireless communication link with the handheld device. The information display may include a display of turn-by-turn information for viewing by the driver of the vehicle. The information display may comprise a video screen.