  We present optical spectra and photometry sampling the first six months after
discovery of supernova (SN) 1999gi in NGC 3184. SN 1999gi is shown to be a Type
II-plateau event with a photometric plateau lasting until about 100 days after
discovery. The reddening values resulting from five independent techniques are
all consistent with an upper bound of E(B-V) < 0.45 mag established by
comparing the early-time color of SN 1999gi with that of an infinitely hot
blackbody, and yield a probable reddening of E(B-V) = 0.21 +/- 0.09 mag. Using
the expanding photosphere method (EPM), we derive a distance to SN 1999gi of
11.1^{+2.0}_{-1.8} Mpc and an explosion date of 1999 December
5.8^{+3.0}_{-3.1}, or 4.1^{+3.0}_{-3.1} days prior to discovery. This distance
is consistent with a recent Tully-Fisher distance derived to NGC 3184 (D ~
11.59 Mpc), but is somewhat closer than the Cepheid distances derived to two
galaxies that have generally been assumed to be members of a small group
containing NGC 3184 (NGC 3319, D = 13.30 +/- 0.55 Mpc, and NGC 3198, D = 13.80
+/- 0.51 Mpc).
  We reconsider the upper mass limit (9^{+3}_{-2} M_{sun}) recently placed on
the progenitor star of SN 1999gi by Smartt et al. (2001, 2002) in light of
these results. Following the same procedures, but using the new data presented
here, we arrive at a less restrictive upper mass limit of 15^{+5}_{-3} M_{sun}
for the progenitor. The increased upper limit results mainly from the larger
distance derived through the EPM than was assumed by the Smartt et al.
analyses, which relied on less precise (and less recent) distance measurements
to NGC 3184.
