  We present an analysis of 8 JWST Mid-Infrared Instrument 5.6 micron images
with 5sigma depths of ~0.1uJy. We detect 2854 sources within our combined area
of 18.4 sq.arcmin -- a >4x increase in source density over earlier IRAC channel
3 data. We compute the MIRI 5.6um number counts including an analysis of the
field-to-field variation. Relative to earlier published MIRI 5.6micron counts,
our counts have a more pronounced knee, at roughly 2\,$\mu$Jy. The location and
amplitude of the counts at the knee are consistent with the Cowley et al.
(2018) model predictions, although these models tend to overpredict the counts
below the knee. In areas of overlap, 84% of the MIRI sources have a counterpart
in the COSMOS2020 catalog. These MIRI sources have redshifts that are mostly in
the z~0.5-2, with a tail out to z~5. They are predominantly moderate to low
stellar masses $10^8-10^{10}$M$_{\odot}$) main sequence star-forming galaxies
suggesting that with $\approx$2hr exposures, MIRI can reach well below $M^*$ at
cosmic noon and reach higher mass systems out to z~5. Nearly 70% of the
COSMOS2020 sources in areas of overlap now have a data point at 5.6micron
(rest-frame near-IR at cosmic noon) which allows for more accurate stellar
population parameter estimates. Finally, we discover 31 MIRI-bright sources not
in COSMOS2020. A cross-match with IRAC channel 1 suggests that 10-20% of these
are likely lower mass (M$_*\approx10^9$M$_{\odot}$), $z\sim1$ dusty galaxies.
The rest (80--90%) are consistent with more massive, but still very dusty
galaxies at z>3.
