Rearview mirror assembly with internally mounted compass sensor

A rearview mirror assembly (100) is disclosed for use in a vehicle that includes a mirror housing (120), a mounting structure (200) for pivotally mounting the mirror housing to the vehicle such that the mirror housing may be both vertically and horizontally tilted, a compass sensor (320) disposed in the mirror housing and coupled to a compass processing circuit. The mirror assembly may include means (380) for compensating for tilting of the mirror housing and may include a tilt detector (500) for detecting when the mirror housing has been tilted from a prior position.