  We present X-ray and radio observations of the new Galactic supernova remnant
(SNR) G306.3-0.9, recently discovered by Swift. Chandra imaging reveals a
complex morphology, dominated by a bright shock. The X-ray spectrum is broadly
consistent with a young SNR in the Sedov phase, implying an age of 2500 yr for
a distance of 8 kpc, plausibly identifying this as one of the 20 youngest
Galactic SNRs. Australia Telescope Compact Array (ATCA) imaging reveals a
prominent ridge of radio emission that correlates with the X-ray emission. We
find a flux density of ~ 160 mJy at 1 GHz, which is the lowest radio flux
recorded for a Galactic SNR to date. The remnant is also detected at 24microns,
indicating the presence of irradiated warm dust. The data reveal no compelling
evidence for the presence of a compact stellar remnant.
