  The mid-infrared provides a unique view of galaxy stellar populations,
sensitive to both the integrated light of old, low-mass stars and to individual
dusty mass-losing stars. We present results from an extended Spitzer/IRAC
survey of M31 with total lengths of 6.6 and 4.4 degrees along the major and
minor axes, respectively. The integrated surface brightness profile proves to
be surprisingly diffcult to trace in the outskirts of the galaxy, but we can
also investigate the disk/halo transition via a star count profile, with
careful correction for foreground and background contamination. Our
point-source catalog allows us to report on mid-infrared properties of
individual objects in the outskirts of M31, via cross-correlation with PAndAS,
WISE, and other catalogs.
