  We present the largest publicly available catalogue of compact groups of
galaxies identified using the original selection criteria of Hickson, selected
from the Sixth Data Release (DR6) of the Sloan Digital Sky Survey (SDSS). We
identify 2297 compact groups down to a limiting magnitude of r = 18
(~0.24groups degree^{-2}), and 74791 compact groups down to a limiting
magnitude of r = 21 (~6.7groups degree^{-2}). This represents 0.9% of all
galaxies in the SDSS DR6 at these magnitude levels. Contamination due to gross
photometric errors has been removed from the bright sample of groups, and we
estimate it is present in the large sample at the 14% level. Spectroscopic
information is available for 4131 galaxies in the bright catalogue (43%
completeness), and we find that the median redshift of these groups is z_{med}
= 0.09. The median line-of-sight velocity dispersion within the compact groups
from the bright catalogue is sigma_{LOS} ~ 230km/s and their typical
inter-galactic separations are of order 50 - 100kpc. We show that the fraction
of groups with interloping galaxies identified as members is in good agreement
with the predictions from our previous study of a mock galaxy catalogue, and we
demonstrate how to select compact groups such that the interloper fraction is
well defined and minimized. This observational dataset is ideal for large
statistical studies of compact groups, the role of environment on galaxy
evolution, and the effect of galaxy interactions in determining galaxy
morphology.
