  We report a scanning superconducting quantum interference device (SQUID)
microscope in a cryogen-free dilution refrigerator with a base temperature at
the sample stage of at least 30 mK. The microscope is rigidly mounted to the
mixing chamber plate to optimize thermal anchoring of the sample. The
microscope housing fits into the bore of a superconducting vector magnet, and
our design accommodates a large number of wires connecting the sample and
sensor. Through a combination of vibration isolation in the cryostat and a
rigid microscope housing, we achieve relative vibrations between the SQUID and
sample that allow us to image with micrometer resolution over a 150 $\mu$m
range while the sample stage temperature remains at base temperature. To
demonstrate the capabilities of our system, we show images acquired
simultaneously of the static magnetic field, magnetic susceptibility, and
magnetic fields produced by a current above a superconducting micrometer-scale
device.
