  Fast Radio Bursts (FRBs) are brief radio emissions from distant astronomical
sources. Some are known to repeat, but most are single bursts. Non-repeating
FRB observations have had insufficient positional accuracy to localize them to
an individual host galaxy. We report the interferometric localization of the
single pulse FRB 180924 to a position 4 kpc from the center of a luminous
galaxy at redshift 0.3214. The burst has not been observed to repeat. The
properties of the burst and its host are markedly different from the only other
accurately localized FRB source. The integrated electron column density along
the line of sight closely matches models of the intergalactic medium,
indicating that some FRBs are clean probes of the baryonic component of the
cosmic web.
