  This paper describes the {\it Chandra} observation of the diffuse emission in
the face-on spiral NGC 6946. Overlaid on optical and H${\alpha}$ images, the
diffuse emission follows the spiral structure of the galaxy. An overlay on a 6
cm polarized radio intensity map confirms the phase offset of the polarized
emission. We then extract and fit the spectrum of the unresolved emission with
several spectral models. All model fits show a consistent continuum thermal
temperature with a mean value of 0.25$\pm$0.03 keV. Additional degrees of
freedom are required to obtain a good fit and any of several models satisfy
that need; one model uses a second continuum component with a temperature of
0.70$\pm$0.10 keV. An abundance measure of 3$^{+1.95}_{-1.90}$ for Si differs
from the solar value at the 90% confidence level; the net diffuse spectrum
shows the line lies above the instrumental Si feature. For Fe, the abundance
measure of 0.67$\pm$0.13 is significant at 99%. Multiple gaussians also provide
a good fit. Two of the fitted gaussians capture the O VII and O VIII emission;
the fitted emission is consistent with an {\it XMM-Newton} RGS spectrum of
diffuse gas in M81. The ratio of the two lines is $<$0.6-0.7 and suggests the
possibility of non-equilibrium ionization conditions exist in the ISM of NGC
6946. An extrapolation of the point source luminosity distribution shows the
diffuse component is not the sum of unresolved point sources; their
contribution is at most 25%.
