The theoretical formulas for ${d}^{6}$ and ${d}^{5}s$ are compared with the experimental data of Mn II. The relative positions of these configurations in Mn II allow the magnitude of configuration interaction to be determined accurately without the use of a least-squares calculation. Over-all agreement between theory and experiment is improved by the use of separate parameters in the two configurations and by the introduction of the effects of configuration interaction. The positions of the terms not yet known experimentally are predicted as a help in further analysis of this spectrum. The positions of terms of the ${d}^{5}s$ configuration are believed to be predicted with better than usual accuracy by the use of a correction term proportional to $L(L+1)$.