57Fe NMR spectra from magnetic domains of BaFe22+Fe163+O27 hexaferrite single crystal were measured at 4.2K using the conventional spin echo technique. External magnetic fields up to 3 T parallel and perpendicular to the hexagonal axis were applied to separate the overlapped NMR lines and to find their correspondence to the seven nonequivalent lattice sites occupied by Fe3+ ions. A pronounced satellite structure of lines from tetrahedral sites was found. These results were analyzed with respect to the distribution of Fe2+ ions among the iron sites.