  We present a multi-wavelength study of the properties of supernova remnants
(SNRs) in the nearby Sculptor Group Sd galaxy NGC 7793. Using our own Very
Large Array radio observations at 6 and 20 cm, as well as archived ROSAT X-ray
data, previously published optical results and our own H-alpha image, we have
searched for X-ray and radio counterparts to previously known
optically-identified SNRs and for new previously unidentified SNRs at these two
wavelength regimes. Only two of the 28 optically-identified SNRs are detected
at another wavelength. The most noteworthy source in our study is N7793-S26,
which is the only SNR that is detected at all three wavelengths. It features a
long (approximately 450 pc) filamentary morphology that is clearly seen in both
the optical and radio images. N7793-S26's radio luminosity exceeds that of the
Galactic SNR Cas A, and based on equipartition calculations we determine that
an energy of at least 10^52 ergs is required to maintain this source. A second
optically identified SNR, N7793-S11, has detectable radio emission but is not
detected in the X-ray. Complementary X-ray and radio searches for SNRs have
yielded five new candidate radio SNRs, to be added to the 28 SNRs in this
galaxy that have already been detected by optical methods. We find that the
density of the ambient interstellar medium (ISM) surrounding these SNRs
significantly impacts the spectral characteristics of SNRs in this galaxy,
consistent with surveys of the SNR populations in other galaxies.
