  We constrained the progenitor masses for 169 supernova remnants, 8
historically observed supernovae, and the black hole formation candidate in NGC
6946, finding that they are consistent with originating from a standard initial
mass function. Additionally, there were 16 remnants that showed no sign of
nearby star formation consistent with a core-collapse supernova, making them
good Type Ia candidates. Using $Hubble$ $Space$ $Telescope$ broadband imaging,
we measured stellar photometry of ACS/WFC fields in F435W, F555W, F606W, and
F814W filters as well as WFC3/UVIS fields in F438W, F606W, and F814W. We then
fitted this photometry with stellar evolutionary models to determine the ages
of the young populations present at the positions of the SNRs and SNe. We then
infer a progenitor mass probability distribution from the fitted age
distribution. For 37 SNRs we tested how different filter combinations affected
the inferred masses. We find that filters sensitive to H$\alpha$, [N II], and
[S II] gas emission can bias mass estimates for remnants that rely on our
technique. Using a KS-test analysis on our most reliable measurements, we find
the progenitor mass distribution is well-matched by a power-law index of
$-2.6^{+0.5}_{-0.6}$, which is consistent with a standard initial mass
function.
